Multiple choice

Let p(x) be a quadratic polynomial such that $p(0)=1$. If p(x) leaves remainder $4$ when divided by $x-1$ and it leaves remainder $6$ when divided by $x+1$; then which one is correct?

  1. $p(2)=11$
  2. $p(-2)=19$
  3. $p(-2)=11$
  4. $p(2)=19$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let p(x) = ax^2 + bx + c. p(0)=1 implies c=1. p(1)=4 implies a+b+1=4 => a+b=3. p(-1)=6 implies a-b+1=6 => a-b=5. Adding: 2a=8, a=4. Subtracting: 2b=-2, b=-1. So p(x) = 4x^2 - x + 1. p(-2) = 4(4) - (-2) + 1 = 16 + 2 + 1 = 19.

AI explanation

Let p(x) = ax^2 + bx + c. From p(0) = 1, we know c = 1. By the polynomial remainder theorem, p(1) = a + b + 1 = 4 and p(-1) = a - b + 1 = 6. Solving these two equations gives a = 4 and b = -1, making the polynomial p(x) = 4x^2 - x + 1. Evaluating p(-2) yields 4(-2)^2 - (-2) + 1 = 16 + 2 + 1 = 19.