3. If \( 3 x^{3}-a x^{2}+2 x+1 \) has a remainder of -3 on division by \( x+2 \), find a. 4. Find both values of ' \( a \) ' for which the polynomials \( 3 x^{2}-7 x-4 \) and \( 32 x^{2}-10 x+6 \) give the same remainder on division by \( x-a \).
Upstudy AI Solution
Answer
Solution
Answered by UpStudy AI and reviewed by a Professional Tutor


Bonus Knowledge
To find the value of \( a \) such that the polynomial \( 3 x^{3}-a x^{2}+2 x+1 \) has a remainder of -3 when divided by \( x+2 \), we can use the Remainder Theorem. This theorem states that the remainder of \( f(x) \) when divided by \( x-c \) is equal to \( f(c) \). So, we evaluate at \( x = -2 \): \[ f(-2) = 3(-2)^{3} - a(-2)^{2} + 2(-2) + 1 \] Calculating this step by step: \[ f(-2) = 3(-8) - a(4) - 4 + 1 = -24 - 4a - 3 \] Setting \( f(-2) = -3 \): \[ -24 - 4a - 3 = -3 \\ -27 - 4a = -3 \\ -4a = 24 \\ a = -6 \] For the second part, we need to find both values of \( a \) such that the polynomials \( 3 x^{2}-7 x-4 \) and \( 32 x^{2}-10 x+6 \) give the same remainder when divided by \( x-a \). Using the Remainder Theorem again, we need: \[ f(a) = g(a) \] Where \( f(x) = 3 x^{2} - 7 x - 4 \) and \( g(x) = 32 x^{2} - 10 x + 6 \). Setting equality: \[ 3a^{2} - 7a - 4 = 32a^{2} - 10a + 6 \] Rearranging gives: \[ 0 = 29a^{2} - 3a + 10 \\ 29a^{2} - 3a + 10 = 0 \] Using the quadratic formula \( a = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \): \[ a = \frac{3 \pm \sqrt{(-3)^{2} - 4(29)(10)}}{2(29)} \\ = \frac{3 \pm \sqrt{9 - 1160}}{58} \\ = \frac{3 \pm \sqrt{-1151}}{58} \] Since we have a negative number under the square root, this indicates \( a \) has complex values. Simplifying, we find: \[ a = \frac{3 \pm i\sqrt{1151}}{58} \] This gives us our final expressions for \( a \).