Solve x2 = 12x – 15 by completing the square. Which is the solution set of the equation?

(negative 6 minus StartRoot 51 EndRoot comma negative 6 + StartRoot 51 EndRoot)
(negative 6 minus StartRoot 21 EndRoot comma negative 6 + StartRoot 21 EndRoot)
(6 minus StartRoot 51 EndRoot comma 6 + StartRoot 51 EndRoot)
(6 minus StartRoot 21 EndRoot comma 6 + StartRoot 21 EndRoot)

1 answer

To solve x^2 = 12x - 15 by completing the square, we first need to rewrite the equation in the form x^2 + bx = c:

x^2 - 12x = 15
x^2 - 12x + 36 = 15 + 36
(x - 6)^2 = 51

Taking the square root of both sides, we get:

x - 6 = ±√51
x = 6 ± √51

Therefore, the solution set of the equation x^2 = 12x - 15 is (6 - √51, 6 + √51).

So the correct answer is (6 minus StartRoot 51 EndRoot, 6 + StartRoot 51 EndRoot).