Question

Using identities evaluate 9.7×9.8

Answer 1

Answer:

9.7×9.8

(10-0.3)(10-0.2)

(x-a)(x-b)=x²-(a+b)x+ab

=(10)²-(0.3+0.2)10+0.3×0.2

=100-0.5×10+0.06

=100-5+0.06

=95.6

9.7×9.8=95.6