Fifteen times the square of a non zero number is equal to 15 times the number what is the number?

1

because

1^2=1

1^2*15=15

1*15=15

So 1^2*15=1*15

Equation looks like this

15x^2=15x

subtract 15x

15x^2+15x=0

factor

15x (x-1) = 0

solutions are 0 or 1 but seeing it said non zero number it must be 1