Question

Which values of a and b make the following equation true?  a = 11, b = 7 a = 11, b = 10 a = 28, b = 7 a = 28, b = 10

Answer 1

we have

$(5x^{7} y^{2})(-4 x^{4} y^{5})=-20 x^{a} y^{b}$

Multiply the terms of the left side of the equation and then compare with the right side to find the values of a and b

$(5x^{7} y^{2})(-4 x^{4} y^{5})=-20 x^{(7+4)} y^{(2+5)}$

$=-20 x^{11} y^{7}$

substitute

$-20 x^{11} y^{7}=-20 x^{a} y^{b}$

Solve for a

$x^{11} =x^{a}$

$a=11$

Solve for b

$y^{7} =y^{b}$

$b=7$

therefore

the answer is

$a=11$

$b=7$

Answer 2

A = 11, b = 7
You just needed to multiply the terms together