Question

Factorize the following
a) x^2-720
b) 15xy+15+9y+25x​

Answer 1

see explanation

Explanation:

(a)

Expressing as a difference of squares

a² - b² = (a - b)(a + b), thus

x² - 720

= x² - (12
`√(5)` )²

= (x - 12
`√(5)` )(x + 12
`√(5)` )

(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

Answer 2

Below

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)