Question: Factorise:
x2 − 7x − 30
Solution:
The given expression is $x^{2}-7 x-30$.
Find two numbers that follow the conditions given below:
Sum $=-7$
Product $=-30$
Clearly, the numbers are $-10$ and 3 .
$x^{2}-7 x-30=x^{2}-10 x+3 x-30$
$=x(x-10)+3(x-10)$
$=(x-10)(x+3)$
