Question

I want to know hot solve this problem

Answer 1

C

Explanation:

`(w^2-9)/(w^2-4w-21)` ( factorise numerator and denominator )

w^2 - 9 ← is a difference of squares and factors as

w² - 9 = (w - 3)(w + 3)

w² - 4w - 21

Consider the factors of the constant term (- 21) which sum to give the coefficient of the w- term ( - 4)

The factors are - 7 and + 3 , since

- 7 × + 3 = - 21 and - 7 + 3 = - 4 , then

w² - 4w - 21 = (w - 7)(w + 3)

Then

`((w-3)(w+3))/((w-7)(w+3))` ← cancel the common factor (w + 3) on numerator/ denominator

=
`(w-3)/(w-7)` → C

Answer 2

I think the answer is A but can be simplified as seen in my photo above