Question

Find the value of the expression 3x3 + 5 (x2-2) for x = (-2).​

Answer 1

Answer:

Let the function be represented by f(x).

As x+2, exactly divides f(x),

−2 is a zero of f(x), hence f(−2)=0

f(x)=2x

3

+5x

2

−x−k

f(−2)=2(−2

3

)+5(−2

2

)+2−k=0

⇒0=−16+20+2−k

⇒k=6