What must be added to 2x4−5x3+2x2−x−3 so that the result is exactly divisible by (x- 2)?
ANSWER:
Let k be added to 2x4–5x3+2x2–x–3 so that the result is exactly divisible by ( x – 2). Here, k is a constant.
∴ f(x)=2x4–5x3+2x2–x–3+k is exactly divisible by ( x – 2).
Using factor theorem, we have
f(2)=0
⇒2×24−5×23+2×22−2−3+k=0⇒32−40+8−5+k=0⇒−5+k=0⇒k=5
Thus, 5 must be added to 2x4–5x3+2x2–x–3 so that the result is exactly divisible by ( x – 2).