Factorise 3x^2 + 14x + 8

To factorise polynomials of the form ax^2 + bx + c, we want to rewrite the middle coefficient as the sum of two smaller numbers. The product of these two numbers should be equal to a * c (in this case, 3 * 8 = 24), and the sum of the two numbers should equal b (in this case, 14). Here, we can see that the values 2 and 12 fit this criteria. Rewriting the original expression would then look like this: 3x^2 + 2x + 12x + 8
From here we can factorise by grouping together the first two terms and the last two terms. By taking the greatest common factor of each group, we get x(3x+2) + 4(3x+2). As (3x+2) appears in both terms here, we can further simplify to (x+4)(3x+2).

AM

Related Maths GCSE answers

All answers ▸

64% of an audience are female. Work out the ratio females : males Give your answer in its simplest form.


a)By completing the square, prove the quadratic formula starting from ax^2+bx+c=0, b) hence, or otherwise solve 3x^2 + 7x -2= 9, to 3s.f.


Find the value of x in the equation x^2 - 2x + 1 = 0


Solve x^2 + 15x = - 50