Question

Factorise a) 4p²-81 b) x²-13x+36

Answer 1

Answer:

A = (2p + 9) (2p - 9)

B = (x - 9) (x - 4)

Step-by-step explanation:

For A : Rewrite 4p^2 as (2p)^2.

(2p)^2−81

Rewrite 81 as 9^2.

(2p)^2−9^2

Since both terms are perfect squares, factor using the difference of squares formula, a^2 − b^2 = ( a + b ) ( a − b ) where a = 2p and b = 9 .

(2p + 9) (2p − 9)

For B : Consider the form x^2 + bx + c . Find a pair of integers whose product is c and whose sum is b . In this case, whose product is 36 and whose sum is − 13 .

-9, -4

(x - 9) (x - 4)

I hope this helps.