Question

(7m – 8n)2 + (7m + 8n)2. ​

Answer 1

Answer:

28m

Step-by-step explanation:

14m - 16n + 14m + 16n

14m + 14m

28m

Answer 2

Answer:

The answer is $98m^2+128n^2$

Step-by-step explanation:

Using the identities

$\boxed{(a-b)^2=a^2+b^2-2ab} \text{ and } \boxed{(a+b)^2=a^2+b^2+2ab}$

We have,

     $(7m-8n)^2+(7m+8n)^2$

    $=(7m)^2+(8n)^2-2(7m)(8n)+(7m)^2+(8n)^2+2(7m)(8n)\\=49m^2+64n^2+49m^2+64n^2\\=98m^2+128n^2$