9514 1404 393
Answer:
x = {5.4, 9.6}
Explanation:
Adding and subtracting the square of half the x-coefficient can help you complete the square.
(x^2 -15x +7.5^2) +52 -7.5^2 = 0
(x -7.5)^2 = 4.25 . . . . . . add the opposite of the constant; write as a square
x = 7.5 ±√4.25 . . . . . . . square root, add 7.5
x ∈ {5.4, 9.6}