Question

Evaluate the following by using suitable a) 202×205 b) 99 square​

Answer 1

Answer:

a) 41410            b) 9801

Step-by-step explanation:

a) 202 x 205 = (200+2) (200+5)

                      $= 200^{2} + 200 (2+5) + (2*5)$    $[(x+a)(x+b) = x^{2} + x(a+b) +a*b]$

                      = 40000  +  200 x 7  +  10  

                      = 40000 + 1400 + 10

                      = 41410

b) 99 square = $(100-1)^{2}$

                     $= 100^{2} -2*100*1 + 1^2$           $[(a-b)^2 = a^2 -2ab + b^2]$

                     $=10000 -200 + 1$

                      $=9801$

NOTE: ' * ' means Multiplication

Answer 2

Answer:

a answer 200+2*200+5

1400

Step-by-step explanation:

200+2×200+5

let we take common

so,

200(2+5)

200(7)

1400

is answer