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