Question

( − 7 x + 9 y ) ( − 9 x − 7 ) − ( − 7 x − 2 y ) ( 4 x + 8 )

Answer 1

$63 {x}^{2} + 49x - 81xy - 63y + 28 {x}^{2} + 56x + 8xy + 16y = 91 {x}^{2} + 105x - 73xy - 47y$

Answer 2

63x²+49x-81xy-63y+28x²+56x+8xy+16y = 91x²+105x-73xy-47y

Answer 3

To simplify the expression:

(−7x + 9y)(−9x - 7) - (−7x - 2y)(4x + 8)

First, apply the distributive property (FOIL) for both terms:

= (-7x * -9x + (-7x) * (-7) + 9y * (-9x) + 9y * (-7)) - (-7x * 4x + (-7x) * 8 - 2y * 4x - 2y * 8)

Now, multiply each term:

= (63x^2 + 49x - 81xy - 63y) - (-28x^2 - 56x - 8xy - 16y)

Now, distribute the negative sign on the second set of parentheses:

= 63x^2 + 49x - 81xy - 63y + 28x^2 + 56x + 8xy + 16y

Combine like terms:

= (63x^2 + 28x^2) + (49x + 56x) + (-81xy + 8xy) + (-63y + 16y)

= 91x^2 + 105x - 73xy - 47y

So, the simplified expression is:

91x^2 + 105x - 73xy - 47y