Evaluate the following products without multiplying directly:
i 103×107
Answers
Here is your solution
Evaluate the following products without multiplying directly
(i)103×107
(100 + 3) (100 + 7)
Now, by using identity :-
(x + a) (x + b) = x² + (a+b)*x + ab
x = 100 , a = 3 , b = 7
Now put value of x , a & b
=> (100)² + (3+7)*100 + (3*7)
=> 10000 + 1000 + 21
=> 11021
(ii)95×96
(90 + 5) (90 + 6)
by using identity :-
(x + a) (x + b) = x² + (a+b)*x + ab
x = 90 , a = 5 , b = 6
Now put value of x , a & b
=> (90)² + (5+6)*90 + (5*6)
=> 8100 + 990 + 30
=> 9120
(iii)104×96
(100 + 4) (100 - 4)
by using identity :-
(x + a) (x + b) = x² + (a+b)*x + ab
x = 100 , a = 4 , b = (-4)
now put value of x , a & b
=> (100)² + { 4 + (-4) }*100 + 4*(-4)
=> 10000 + (4 - 4)*100 - 16
=> 10000 + 0*100 - 16
=> 10000 - 16
=> 9984
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