Question

Which equation is true?

Answer 1

Answer : $9x^2 - 25 = (3x - 5)(3x + 5)$

(1) $9x^2 - 25 = (3x - 5)(3x - 5)$

Use FOIL method to mulitply (3x – 5)(3x – 5)

$(3x - 5)(3x - 5) = 9x^2 - 30x + 25$

(2) $9x^2 - 25 = (3x - 5)(3x + 5)$

Use FOIL method to mulitply (3x - 5)(3x + 5)

$(3x - 5)(3x - 5) = 9x^2 - 15x + 15x - 25 = 9x^2 - 25$

(3) $9x^2 - 25 = -(3x + 5)(3x + 5)$

Use FOIL method to mulitply -(3x + 5)(3x + 5)

$-(3x + 5)(3x + 5) = -(9x^2 + 30x + 25) = -9x^2 -30x -25$

(4) $9x^2 - 25 = -(3x + 5)(3x - 5)$

Use FOIL method to mulitply -(3x + 5)(3x - 5)

$-(3x + 5)(3x - 5) = -(9x^2 - 25) = -9x^2 + 25$

So equation 2 is true

Answer 2

Hello,

Answer B


But this is not an equation!!!!! (only an expression)