What is the discriminant of 9x2 + 2 = 10x?

a. - 356

b.-172

c. 28

d. 72

Discriminant is 28 (c) First get the equation into the form: Ax^2 + Bx + C = 0 (the quadratic equation) ... By subtracting 10x both sides (to get it on the other side) ... 9x^2 + 2 = 10x 9x^2 - 10x + 2 = 10x - 10x 9x^2 - 10x + 2 = 0 Now the discriminant is: b^2 - 4ac The quadratic equation is Ax^2 + Bx + C = 0 Here, A = 9, B = - 10 and C = 2 (-10) ^2 - 4 (9) (2) = 100 - 4 (18) = 100 - 72 = 28