Below
Step-by-step explanation:
a)
● x^2 - 720
● x^2 - √(720)^2
● ( x + √720) ( x - √720)
b)
● 15xy + 15 + 9y + 25x
● 5x ( 3y + 5) + 15 + 9y
● 5x ( 3y + 5) + 3 ( 5 + 3y)
● ( 3y + 5) ( 5x + 3)
see explanation
Step-by-step explanation:
(a)
Expressing as a difference of squares
a² - b² = (a - b)(a + b), thus
x² - 720
= x² - (12 )²
= (x - 12 )(x + 12
)
(b)
15xy + 15 + 9y + 25x ← rearrange
= 15xy + 9y + 25x + 15 ( factor the first/second and third/fourth terms )
= 3y(5x + 3) + 5(5x + 3) ← factor out (5x + 3)
= (5x + 3)(3y + 5) ← in factored form
joined
Step-by-step explanation: