
Factorising Quadratics
 
Here are worked solutions to the problems on the previous page.
 x² + 7x + 10 = 0.
10 = 2 × 5 and 2 + 5 = 7 so:
(x + 2)(x + 5) = 0
Solutions: x=2 and x=5
 x² + x  30 = 0.
30 = 5 × 6 and 5 + 6 = 1 so:
(x + 6)(x  5) = 0
Solutions: x=6 and x=5
 x²  10x  24 = 0.
24 = 12 × 2 and 12 + 2 = 10 so:
(x  12)(x + 2) = 0
Solutions: x=12 and x=2

If you got one or more right: very well done! This is not easy. If you got any wrong, make sure you can see why.
