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Published on: 26/09/2019
Exponents and Powers
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Questions + Answers key
Take MCQ Mathematics Test

1.
Find the value of:
100 x (-1)100
2.
Find the value of:
2 x (-2)4
3.
Express the following as a product of prime factors:
216
4.
Which is greater-32 or 23?
5.
Are a3b2 and a2b3 the same?
6.
Simplify the following and write the answer in exponential form:
\([{5^6\over 5^3}]\times 5^2\)
7.
Find five more such examples, where a number is expressed in exponential form. Also identify the base and the exponent in each case
8.
Simplify:
\(\frac{10\times 5^{n+1}+25\times 5^n}{3\times 5^{n+2}+10\times 5^{n+1}}\)
9.
Write the number from the given expanded form: 4 x 104 + 5 x 103 + 3 x 102 + 4 x 101+ 2 x 100
10.
By using laws of exponents and simplify: \(\frac { { a }^{ 4 }\times { a }^{ -2 }\times { b }^{ 4 } }{ { b }^{ 2 }\times { a }^{ 8 }\times { a }^{ -6 } } \)
11.
Write the difference between 83 and 73
12.
If 2n+2 - 2n+1 +2n = c x 2n, then find the value of c.
13.
Find the value of n, where n is an integer and \({ 2 }^{ n-5 }\times { 6 }^{ 2n-4 }=\frac { 1 }{ { 12 }^{ 4 }\times 2 } \).
14.
Express each of the following numbers using exponential notations.
1029
15.
Express each of the following numbers using exponential notations.
1024
1.
100
2.
32
3.
23 x 33
4.
32>23
5.
NO
6.
we have \([{5^6\over 5^3}]\times 5^2\) =[56-3]x52 \((\because {a^m\over a^n}=a^{m-n})\)
= 53 X 52
= 53 + 2 \((\because a^m \times a^n =a^{m+n})\)
= 55
Thus,\([{5^6\over 5^3}]\times 5^2=5^5\)
7.
| Number | Exponential form | Base | Exponent |
| (i) 243 = 3 x 3 x 3 x 3 x 3 | 35 | 3 | 5 |
| (ii) 625 = 5 x 5 x 5 x 5 | 54 | 5 | 4 |
| (iii) 343 = 7 x 7 x 7 | 73 | 7 | 3 |
| (iv) 1331 = 11 x 11 x 11 | 113 | 11 | 3 |
| (v) 64 = 8 x 8 | 82 | 8 | 2 |
1. x \(\times\) x \(\times\) x \(\times\)x = x4 is read as 'x raised to the power 4' or '4th power of x'.
2.x5y5 is read as 'x squared into y raised to power 5'.
3. p6q3 is read as 'p raised to the power 6 into q cubed'.
8.
\(\frac{10\times 5^{n+1}+25\times 5^n}{3\times 5^{n+2}+10\times 5^{n+1}}\)
\(=\frac{2\times 5\times 5^n\times 5^1+5\times5\times5^n}{3\times5^n\times5^2+2\times5\times5^1\times5^n}\)
\(=\frac{2\times5\times5^n\times5+5\times5\times5^n}{3\times5^n\times5\times5+2\times5\times5\times5^n}\)
\(=\frac{5\times5\times5^n\times2+5\times5\times5^n}{5\times5\times5^n\times3+5\times5\times5^n\times2}\)
\(=\frac{5\times5\times5^n(2+1)}{5\times5\times5^n(3+2)}=\frac{(2+1)}{(3+2)}\)
\(=\frac{3}{5}\)
9.
45342
10.
b2
11.
169
12.
Given, 2n+2- 2n = c x 2n
⇒ 2n+2 = 2n x 22, 2n+1 = 2n x 21
So, 2n x 22 - 2n x 21 + 2n = c x 2n
Taking ~ common from both the side, we get
2n (22-21)= c x 2n
⇒ (22-21+1)c
∴ c = 4-2+1 [∵ 22= 2 x 2=4, 21=2]
=2 +1 =3
13.
Given, \({ 2 }^{ n-5 }\times { 6 }^{ 2n-4 }=\frac { 1 }{ 12^{ 4 }\times 2 } \)
∵ 62n-4 = (2 x 3)2n-4 = 22n-4 x 32n-4
and 124 = (3 x 4)4 =(3 x 2 x 2)4 = 34 x 24 x 24
So, 2n-5 x 22n-4 x 32n-4 =\(\frac { 1 }{ { 3 }^{ 4 }\times { 2 }^{ 4 }\times { 2 }^{ 4 }\times { 2 }^{ 1 } } \)
⇒ 2n-5+2n-4 x 32n-4 =\(\frac { 1 }{ { 3 }^{ 4 }\times { 2 }^{ 4+4+1 } } \)
[∵ am x an =am+n]
⇒ 23n-9 x 32n-4 = \(\frac { 1 }{ { 3 }^{ 4 }\times { 2 }^{ 9 } } \)
⇒ 23n-9 x 32n-4 = 3-4 x 2-9
[∵ a-m=\(\frac { 1 }{ { a }^{ m } } \)]
am =an ⇒ m=n
So,3n-9 = -9
3n = - 9 + 9 = 0 ⇒ n = 0
14.
Given, 1029
∵ 1029 = 3 x 7 x 7 x 7 = 3 x 73

The exponent form of 1029 is 3 x 73.
15.
Given, 1024
∵ 1024 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 210

The exponent form of 1024 is 210.
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