Question

solve the cubic equation 2x^3-x^2-18x+9=0 if sum of two of its roots vanishes​

Answer 1

the cubic polynomial - 2x³-x²-18x+9 =0

= x²(2x+1) -9(2x+1)

= x²-9. and 2x+1

= x = 9 , -9 and -1/2