Question

Using identities find the following
4Marks u can get 40 points

I) (9.8)^2
ii) 298×302
iii) 125^2-75^2
iv) 109×110

Answer 1

I) by using (a-b)^2=a^2 +b^2 - 2ab
(9.8)^2
=(10-0.2)^2
= 100 + 0.04 - 4
= 96.04
ii) by using (a-b)(a+b) = a^2 -b^2
298 * 302
= (300-2)(300+2)
= 90000-4
=89996