#### Answer

Chapter 6 - Section 6.1 - Practice: 4 (Answer)
(a) 10y + 25 = 5(2y + 5)
(b) $x^4 – x^9$ = $x^4(1 – x^5)$

#### Work Step by Step

Chapter 6 - Section 6.1 - Practice: 4 (Solution)
(a) Factorize : 10y + 25
The GCF of terms 10y and 25 is 5, thus,
10y + 25 = 5(2y + 5) (Apply the distributive property)
(b) Factorize : $x^4 – x^9$
The GCF of terms $x^4$ and $x^9$ is $x^4$, thus
$x^4 – x^9$ = $x^4(1 – x^5)$ (Apply the distributive property and product rule)