4(x + 2)(x + 9)
Explanation:4x² + 44x +72
a = 4, b = 44, c = 72
a(c) = 4(72) = 288
The factors of 288 whose sum gives 44 are 36 and 8
4x² + 36x + 8x +72
4x(x + 9) + 8(x + 9)
(4x + 8)(x + 9)
To factorise completely, 4 is common to the first parenthesis:
(4x + 8) = 4(x + 2)
The factorisation of 4x² + 44x +72:
4(x + 2)(x + 9)
