Question

When the polynomial $2 x^3 - ax^2 + 9 x - 8$ is divided by $x - 3$ the remainder is $28$.
Find the value of $a$ .

Answer 1

P(x)= 2x³ - ax² + 9x - 8 x-3=0 x=3 P(3)=28 2 * 3³ - a*3² + 9*3-8=28 54-9a + 27 - 8 = 28 -9a = 28-54-27+8 -9a = -45 a =45 ÷ 9 a = 5 Therefore, a=5