Question

If one of the quadratic polynomial (k-1) x^2+kx+1 is -3 then the value of k is

Answer 1

Here one of the values of x is given in a quadratic polynomial. For finding the value of x we'll put the value in the polynomial.

By putting the value of x in the quadratic polynomial, i.e. -3 we get :

⟶ (k - 1)x² + kx + 1 = 0

⟶ (k - 1)(-3)² + k(3) + 1 = 0

⟶ (k - 1)9 + 3k + 1 = 0

⟶ 9k - 9 + 3k + 1 = 0

⟶ 9k + 3k - 8 = 0

⟶ 12k - 8 = 0

⟶ 12 k = 8

⟶ k = 8/12

⟶ k = ⅔

∴ Hence, the value of k is ⅔