Question

Show that 4x+3 is a factor of 4x³+3x²-28x-21 and hence factorise completely

Answer 1

Step-by-step explanation:

putting 4x + 3 = 0

x = -3/4

now substituting it in the given equation;

4 × (-3/4)^3 + 3 × (-3/4)^2 - 28 × (-3/4) - 21

= -27/16 + 27/16 + 21 - 21

= 0

hence proved