Question

1. 36(a+b)^2 - 49(a-b(^2

2.x^2 - y^2 - 9z + 6yz
3. Find the value if x=16 & y=5
X^2 + y^2 + xy
____________(THE line means division)
X^3 - y^3

Answer 1

-13a^2 + 170ab - 13b^2.

Explanation:

1. 36(a+b)^2 - 49(a-b)^2

This is the difference of 2 squares: a^2 - b^2 = (a + b)(a - b).

36(a+b)^2 - 49(a-b)^2

= (6(a + b) + 7(a - b))( 6(a + b) - 7(a - b))

= (6a + 7a + 6b - 7b)( 6a - 7a + 6b + 7b)

= (13a - b)(-a + 13b)

If you require the expansion of this it is:

-13a^2 + 170ab - 13b^2.