Let \(f(x)=2 x^{3}-3 x^{2}-5 x+6\). If \(x-1\) divides \(f(x)\) find the zero of the function.
A. 1,2,3 / 2 B. 1,2,-3 / 2 C. -1,2,3 D. 1,-2,-3 / 2
Correct Answer: B
Explanation
The zeroes of the function are the roots of the given equationy the remainder theorem. since \(x-1\) divides \(f(x)\). then by long division \(\frac{-x^{2}+x}{-6 x+6}\) \(-6 x+6\) \(\Longrightarrow 2 x^{2}-x^{2}-5 x^{2}+6\) \(\equiv(x-1)\left(2 x^{2}-x-6\right)\) we then factorise \(2 x^{2}-x-6\) to obtain \((x-2)(2 x+3)\) \(\therefore\) The zeroes are \(x=1 . x=2\) and \(x=-3 / 2\)