Year 10 Interactive Maths - Second Edition

Factors of Quadratic Trinomials of the Type ax² + bx + c

 7x×2 + x×1 = 14x+ x = 15x.  We reject this pair as the middle term is 9x.

Note:

The solution is read across.

Use of a Common Factor

If a quadratic trinomial has a common factor, take it out and place it in front of the brackets.  Then use the cross-multiplication method to factorise the quadratic trinomial.

Example 10

Solution:

Check:

Note:

The common factor 2 was taken out first to make the factorisation simpler.

Example 11

Solution:

Now try the factors 2a and 3a.

Check:

Note:

The common factor 3 was taken out first to make the factorisation simpler.