Lisa bought 15 CDs in December. Of those, 3 were jazz, the rest were world
music. How many world music discs did she buy?

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x

its 4 because 2 times 2 is 4, if you double the number two you get four