Question

Using remainder Theorem, factorise: 2x³ + 7x² − 8x – 28 Completely.

Answer 1

Let f (x) = 2x³ + 7x² − 8x − 28

For x = 2,

f(x) = f(2) = 2(2)³ + 7(2)² − 8(2) − 28 = 16 + 28 − 16 − 28 = 0

Hence, (x − 2) is a factor of f(x).