Question

19. Expand :
(i) (x - 2y + 6) (x – 2y – 6).
(ii) (2a - 4b + 7) (2a + 4b + 7).​

Answer 1

Answer:

Answers below

Step-by-step explanation:

(1) (x - 2y + 6) (x – 2y – 6)

= x^2-4xy+4y^2-36

(2) (2a - 4b + 7) (2a + 4b + 7)

=4a^2+28a+49-16b^2

=4a^2+28a-18b^2+49

I used

(a+b)(a-b)=a^2-b^2