Question

Fifteen times the square of a non-zero number is equal to 20 times number.

Answer 1

15 * x^2 = 20x

that's what the question discribed.
now solve for x

x = 4/3

Answer 2

Let the number be x

15 × x² = 20 × x
⇒ 15x² = 20x
⇒ 15x² / x = 20
⇒ 15x = 20
⇒ x = 20/15
⇒ x = 4/3

The number is 4/3

Hope it helps!