Question

three times the square of a non-zero number is equal to fifteen times the number.. what is the number?

Answer 1

3 * (x^2) = 15x
3x^2 -15x = 0
x= - -15 +- sq root (225 -4*3*0) / 2*3
x = [15 +-sq root (225 -4*3*0] / 6
x1 = [15 +15] / 6
x1 = 5

x2 = [15 -15] / 6
x2 = 0

The number is 5

Check
3 * 5^2 = 15 * 5
75 = 75