Question

Factorise:x^2+5x+6
By using (x+a)(x+b)=x^2+(a+b)x+ab

Answer 1

1)x² +5x + 6 
=x²+2x+3x+2*3
=x²+(2+3)x+2*3---(1)

2)x²+5x+6
= x²+2x+3x+6
=x(x+2)+3(x+2)
=(x+2)(x+3)----(2)
therefore
(2)= (1)
(x+2)(x+3) = x²+(2+3)x+2*3