Assuming that x, y, z are positive real numbers, simplify each of the following:
(i) (ii) (iii) (x-2/3y-1/2)2 (iv) (v) (vi)
(i) ( )5 = (1 / x3/2) 5
= (1 / x 3/2 × 5) = (1 / x 15/2)
(ii) (3 / y2) = (x3 / y2) 1/2
= x3 × 1/2 / y2 × 1/2
= x3/2 / y
(iii) 1 / (x2/3 y1/2)2
= 1 / (x2/3 × 2 y1/2 × 2)
= 1 / x4/3 y
(iv) (x1/2)-2/3 (y)2 / (xy-1/2)1/2
= x-1/3y2 / (x1/2y-1/2×1/2)
= (x-5/6) (y9/4)
= (y9/4) / (x5/6)
(v) (243x10 y5 z10) 1/5
= (35)1/5 x2yz2
= 3x2yz2
(vi) (y10 / x4)5/4
= y 10 × 5/4 / x4 × 5/4
= y25/2 / x5
Simplify:
(i) (16-1/5)5/2 (ii) (iii) (0.001)1/3 (iv) (v) (vi)
(i)
We know for any non-zero number a,
(am)n = amn
So,
As we know 42 = 16
Therefore,
= 4-1
As we know for any non-zero number a,
a-1 = 1/a
So 4-1 = 1/4
(ii) [(343)-2]1/3
We know for any non-zero number a,
(am)n = amn
So,
As we know 73 = 343
Therefore,
= 7-2
As we know for any non-zero number a,
a-1 = 1/a
So 7-2= 1/72
= 1/49
(iii) ()1/3 = (1 / 103) 1/3
= = 0.1
(iv)
We know 25 = 52
243 = 35
16 = 24
8 = 23
So,
We know for any non-zero number a,
(am)n = amn
So,
(v)
We know that for any non-zero number a,
am ÷ an = am-n
So,
As we know for any non-zero number a,
a-1 = 1/a
(vi)
We know for any non-zero number a,
(am)n = amn
So,
We know for any non-zero number a,
am × an = am+n
= 25 × 7
= 175
Prove that:
(i)
(ii) 93/2 -3× 50 - = 15
(iii) -3×82/3 ×40+
(iv) = 10
(v) + (0.01)-1/2 – (27)2/3 =
(vi)
(vii)
(viii) = 28
(ix)
(i) (31/2+1/6.5-3/2 +1) / (3-1/3.51/2)
=(32/3.5-1/2) / (3-1/3.51/2)
=(32/3 + 1/3) / (51/2 +1/2)
=3/5
(ii) (32 )3/2 -3.1 – (1/92)-1/2
= 33 -3 -9
=27 -3 -9
=27-12
=15
(iii) 2(-2)(-2) -3.82/3 +(3/4)-1
=24 -3.22 + 4/3
=16 -12 + 4/3
=16/3
(iv) [(2.31/3)/(2-1/5 52/5)] × (2-1/5.3)/ (34/3.57/5)
= 2.31/3 +1 -4/3 / 52/5-7/5
= 2.5
=10
(v) 1/2 + 1/(0.01)1/2 -32
=1/2 + 10 – 9
=1/2 + 1
=3/2
(vi) (2n + 2n-1)/ ) (2n+1 - 2n)
=2n(1 + 2-1 ) / 2n (2-1)
= [1 + (1/2)]/1
=1 + 1/2
=3/2
(vii) (125/64)2/3 + (625/256)1/4 + ( 5/4)
=(5/4)2 + 5/4 + 5/4
=25/16 + 5/4 + 5/4
=65/16
(viii) (3-3.62.7(2)1/2)/ (54/3.(15)-4/3‑.31/3) =28(2)1/2
(3-3.36.7(2)1/2)/ (54/3-4/3.(3)-1)
(3-2.36.7(2)1/2)/ (50)
1/9.36.7(2)1/2
28
(ix) {1- 1/0.1}/ { (3/8)-1(3/2)3 + (-1/3)-1
=1-10/{ (8/3)(3/2)3 + (-3)
=-9/(32-3)
= -3/2
If 27x =, find x.
We have,
(27)x = 9 / 3x
(33)x = 32 / 3x
33x = 3 2 – x
3x = 2 – x {On equating exponents}
3x + x = 2
4x = 2
x = =
Hence, the value of x is
Find the values of x in each of the following:
(i) 25x÷ 2x =
(ii) (23)4 = (22)x
(iii)
(iv) 5x-2 × 32x-3 = 135
(v) 2x-5 × 5x-4 = 5
(vi) 2x-7 × 5x-4 = 1250
(i) we have,
25x÷ 2x =
25x/2x = 220/5
25x-x = 24
4x = 4
x=1
(ii) We have,
(23)4 = (22)x
23.4 = 22.x
12 = 2x
X=6
(iii) We have,
52x-x/ 32x-x = ()3
5x/3x = ()3
()x = ()3
x=3
(iv) We have,
5x-2 × 32x-3 = 135
5x-2 × 32x-3 = 5
5x-2 × 32x-3 = 513
x-2 =1 ; 2x-3 =3
x=3 ; x= 3
(v) We have,
2x-5 × 5x-4 = 5
2x-5 × 5x-4 = 51 × 20
x-5=0 ; x-4 = 1
x= 4 ; x=1 +4 =5
(vi) We have,
2x-7 × 5x-4 = 1250
2x-7 × 5x-4 = 21 × 54
x – 7=1; x-4 = 4
x= 8; x= 4+4 = 8
The value of {2-3(2-3)3}3 is
A. 5
B. 125
C. 1/5
D. -125
{2-3(2-3)3}3
= {2 – 3 (-1)3}3
= {2 + 3}3
= 53 = 125
Write (625)-1/4 in decimal form.
= 0.2
State the product law of exponents.
The product law of exponent states that while multiplying two parts having same base, you can add the exponents.
(256)0.16 × (256)0.09
A. 4
B. 16
C. 64
D. 256.25
(256)0.16 × (256)0.09
= (256) 0.16 + 0.09
= (256) 0.25
= 44 × = 4
State the quotient law of exponents.
The quotient law of exponent states that to divide two exponents with the same base, you keep the base and subtract the powers.
If 102y = 25, then 10-y equals
A.
B.
C.
D.
102y = 25
= 10y = x
= x2 = 52
= x = 5
= 1/x = 10-y
= 1/5
State the power law of exponents.
The power law of exponents states that:
(an)m = an.m
Example: (23)2 = 23.2
= 26 = 64
The value of x-yx-y when x = 2 and y = -2 is
A. 18
B. -18
C. 14
D. -14
x – y x – y
= 2 – (-2)(2 + 2)
= 2 – 16 = - 14
The product of the square root of x with the cube root of x is
A. Cube root of the square root of x
B. Sixth root of the fifth power of x
C. Fifth root of the sixth power of x
D. Sixth root of x
×
= x1/2 × x1/3
= x5/6
For any positive real number x, find the value of
x(a – b) (a + b) × x(b – c) (b + c) × x(c – a) (c + a)
= xa.a - b.b × xb.b – c.c × xc.c – a.a
= xa.a – b.b + b.b – c.c + c.c – a.a
= xo = 1
For any positive real number x, write the value of
(x)ab × 1/ab . (x)bc . 1/bc . xca . 1/ca
= x . x . x
= x3
If 9x+2 = 240 + 9x, then x =
A. 0.5
B. 0.2
C. 0.4
D. 0.1
9x + 2 = 240 + 9x
9x × 92 = 240 + 9x
Let 9x = y
81y = 240 + y
80y = 240
y =
9x = 3
32x = 3
2x = 1
x = = 0.5
Write the value of {5(81/3 + 271/3)3}1/4
{5(81/3 + 271/3)3}1/4
= {5 (2 + 3)3}1/4
= (54)1/4 = 5
Simplify .
The seventh root of x divided by the eighth root of x is
A. x
B.
C.
D.
x1/7 / x1/8
= (x)1/7 – 1/8
= (x)1/56
=
The square root of 64 divided by the cube root of 64 is
A. 64
B. 2
C.
D. 642/3
As 64 can be written as 64 = 2×2×2×2×2×2
so 64 = 26
√64=√(26)=(26)1/2 = 23=8
=(26)1/3 = 22=4
= = 2
If (x-1)3 = 8, what is the value of (x+1)2
(x – 1)3 = 8
x – 1 = 2
x = 3
(x + 1)2 = (3 + 1)2
= 42 = 16
Which of the following is (are) not equal to ?
A.
B.
C.
D.
= 1 / {(5/6)1/5}1/5
= (5/6)-1/30
= (6/5)1/30
When simplified (x-1 + y-1)-1 is equal to
A. xy
B. x + y
C.
D.
(x-1 + y-1)-1
= ( + ) -1
= () -1
= ()
If 24×42 = 16x, then find the value of x.
24 × 24 = 16x
28 = 24 × x
x = 24 = 16
If 3x-1=9 and 4y+2 = 64, What is the value of .
3x – 1 = 32
x – 1 = 2
x = 3
4y + 2 = 43
y + 2 = 3
y = 1
x / y = 3/1 = 3
If 8x+1 = 64, what is the value of 32x+1?
A. 1
B. 3
C. 9
D. 27
8 x + 1 – 64
= 8 x + 1 = 82
On equating powers, we get
x + 1 = 2
x = 1
= 3 2x + 1
= 33 = 27
Write the value of .
= (7 . 72)1/3
= (7)3×1/3
= 7
If 0 < y < x, which statement must be true?
A.
B.
C.
D.
Since, it is the property of square roots.
Write × (64)-1/3 as a rational number.
× (64)-1/3
= (32)1/2 × (1/43) -1/3
= 3 × 1/4 = 3/4
If x is a positive real number and x2 = 2, then x3 =
A.
B. 2
C. 3
D. 4
x2 = 2
x =
x3 = (2)1/2 × 3
= 2
Write the value of.
= (53 × 33)1/3
= 5 × 3
= 15
If (23)2 = 4x, then 3x =
A. 3
B. 6
C. 9
D. 27
(23)2 = 22x
2x = 6
x = 3
If 10x = 64, what is the value of?
A. 18
B. 42
C. 80
D. 81
can be written as: (10x)1/2 × 10
= (64)1/2 × 10
= 8 × 10
= 80
If = 8x-1 and x > 0, then x =
A.
B. 2
C. 4
D. 64
If g = t2/3 + 4t-1/2, what is the value of g when t = 64?
A.
B.
C. 16
D.
g = t2/3 + 4t-1/2
= (64)2/3 + 4 (64) -1/2
= [(64)1/3]3 + 4 () 1/2
= 42 + 4 ()
= 16 + =
If x-2 = 64, then x1/3 + x0 =
A. 2
B. 3
C. 3/2
D. 2/3
()2 = (8)2
= 8
x =
x1/3 + xo
= ()1/3 + ()o
= + 1 =
If 4x – 4x-1 = 24, then (2x)x equals
A. 5
B.
C. 25
D. 125
4x – 4x – 1 = 24
Let 4x = y
y - = 24
4y – y = 96
y = 32
4x = 32
22x = 25
(2x)x = (2 × )5/2
= (5)5/2 = 25
When simplified is
A. 9
B. -9
C.
D.
(-27) 2/3
= (3)3 × 2/3
= 9
Which one of the following is not equal to ?
A.
B. 8-1/6
C.
D.
1 / (8)-1/2 × 1/3
= 2-1/2
=
Which one of the following is not equal to ?
A.
B.
C.
D.
1 / (100/9)3/2
= (10/3)-3/2 × 2
=
When simplified is
A. 8
B.
C. 2
D.
1 / 2561/8
= 1/28 × 1/8
= 1/2
is equal to
A.
B.
C.
D.
5n (25 – 30) / 5n (13 – 10)
= -5 / 3
If a, b, c are positive real numbers, then is equal to
A. 1
B. abc
C.
D.
(b/a)1/2 × (c/b)1/2 × (a/c)1/2
= (b/a × c/b × a/c)1/2
= 1
If, then x =
A. 2
B. 3
C. 5
D. 4
= 5x × 32x – 8 = 55 × 33
Comparing the coefficient of x we get,
= x = 5
If , then x=
A. 2
B. 3
C. 4
D. 1
(3/2)-x (3/2)2x = (3/2)4
= (3/2)-x + 2x = (3/2)4
= -x + 2x = 4
= x = 4
The value of is
A.
B. 2
C.
D. 4
= {2-4 2-2}1/2
= {1/16 × 22}1/2
=
If a, b, c are positive real numbers, then is equal to
A. 5a2bc2
B. 25ab2c
C. 5a3bc3
D. 125a2bc2
(3125a10b5c10)1/5
= 5a2bc2
The value of 64-1/3 (641/3 – 642/3), is
A. 1
B.
C. -3
D. -2
64-1/3 (641/3 – 642/3)
= 4-1 (4 – 42)
= (4 – 16)
= = -3
If = 125, then 5 =
A. 25
B.
C. 625
D. 10
= 125
5n/2 = 53
n/2 = 3
n = 6
5 = 5 (64)1/6
= 5 (2)6/6 = 10
If (16)2x+3 =(64)x+3, then 42x-2 =
A. 64
B. 256
C. 32
D. 512
44x + 6 = 4 3x + 9
= 4x + 6 = 3x + 9
= x = 3
42x – 2 = 44
= 256
If a, m, n are positive integers, then is equal to
A. amn
B. a
C. am/n
D. 1
We know for any non-zero number a,
am × an = am+n
Again using (am)n = amn we get,
=a
If 2-m×, then is equal to
A.
B. 2
C. 4
D.
2-m × 1 / 2m = 1/4
= 1/2m × 1/2m = 1/4
= 1/4m = 1/4
= m = 1
1/14 {(4m)1/2 + (1/5m)-1}
= 1/14 {2 + 5}
= 1/14 × 7
=
If x = 2 and y = 4, then +=
A. 4
B. 8
C. 12
D. 2
(2/4) 2 – 4 + (4 / 2)4 – 2
= (1/2)-2 + 22
= 22 + 22
= 8
The value of m for which = 7m, is
A.
B.
C. -3
D. 2
[{74}-1/3]1/4
= (1/74)1/3 × 1/4
= (1/7)1/3 = 7m
= 7 -1/3 = 7m
= m = -1/3
If = 16,and a = 21/10, then =
A. 2
B.
C. 9
D.
2m + n - n + m = 24
22m = 24
2m = 4
m = 2
Also a = 21/10
= a2m + m + n - 2n - p + 2p
= a3m - n + p
The value of {(23+22)2/3+(140 – 19)1/2}2, is
A. 196
B. 289
C. 324
D. 400
= {32 + 11}2
= (9 + 11)2
= (20)2 = 400
If = 1024, then=
A. 3
B. 9
C. 27
D. 81
= 210
2n/2 = 210
= 10
= 32 (n / 4 – 4)
= 32 (20/4 – 4)
= 32 = 9
If = 37, then x =
A. 3
B. -3
C.
D.
= 37
= 35x × 38 × 38/ 32x = 37
= 35x + 16 – 2x = 37
= 5x + 16 – 2x = 7
= 3x + 16 =7
= 3x = -9
x = -3