Answer:
x = 18
Explanation:
Since this is a right triangle, we can use the Pythagorean theorem
a^2 + b^2 = c^2
x^2 + 24^2 = ( 12+x)^2
FOIL the right side
x^2 +576 = 144 + 24x + x^2
Subtract x^2 from each side
576 = 144 + 24x
Subtract 144 from each side
576-144 = 24x
432 = 24x
Divide each side by 24
432/24 = 24x/24
18=x