Question

Factorise: y² + 7y – 144

Answer 1

First find the two numbers whose sum= 7 and product= -144

Clearly, the numbers are 16 and -9

∴ we get, y² + 7y – 144 

= y² + 16y – 9y – 144

= y(y+16) – 9(y+16)

= (y+16) (y-9)