Page 39 - ICSE Math 8

6 –4 6 3m 6 5
(d) The value of m for which × = is –3.
13 13 13
55
97
60
18
(e) The value of (2) × (2) – (2) × (2) is 0.
3. Fill in the blanks.
m
n
(a) (x) = (x) ⇒ __________________ (b)  p   − m =    m


 q   
PRACTICE TIME

p  4 −4  2  − 5 1
− 
1. Write in the form : (a) (b) (c)
q     4 () − 2
 5
3 


2. Find the value.
   1  − 1  1   − 1
−
1

0
–1
2
–2 0
–2
–2
(a) {(6) + (2) } × 3 (b) {(2) + (3) + (4) } (c)    −   
5 

6 

3. Simplify.    
3

−
   1  − 3  1     − 3
1
–1
–3
0
–3
–1
–1
(a)    −    ÷   (b) {(2) + (3) } × (7) (c) {(1) + (2) + (3) } ÷ (4) –1
   3   2     4  −1
− 
–1
4. By what number should (2) be multiplied to get the product as  7  ?

5. Express the following as a power with base 2.  4 
–5
6
–3
(a) (4) (b) (8) (c) (4) (d) (16) 3
6. Write as a rational number with negative exponent. − 2

3

6  
(a)  1  4 (b) (2) 5 (c)      
 
 6     7    −2 −1

2
1
2 
3
3
7. Simplify: (a) {(3) – (2) } ×    − 3 (b)        −    
 
 3      2    
 
–7
8. Find m if: (a) (3) ÷ (3) –10 = (3) 2m – 1 (b)  −  1  3m ×  −  1  2 =   −  1  m − 6


 4   4   4 
9. The population of a bacteria grows 10,000 times in 10 hours. If the initial number of bacteria is 30, find
the population of bacteria after 20 hours.
10. A sum of ` 2,000 is deposited in a bank at the rate of 5% compounded annually. Find the amount after
R n
3 years. [C.I = P 1 + – 1}, where P is principal, R is rate and n is time]
100
THINK SMART
1. Find x, if:
− 
− 
1 
− 
(a)  1  − 8 ×  1  − 4 =    − 4x (b)  −  1  −18 ÷   −  1  7 =  −  1  −2x + 1 (c)  3  14 ×  3  −3 =  3  3x + 2



 
 


 5   5   5   3   3   3   5   5   5 
5
1
p   −2   2  p  −3
2. If =   ÷   , find the value of .
q      q  
5
6

27