Answer:
1 ± √47
Explanation:
Combine like terms in 2x^2 +3 x-7 =x^2 +5x +39:
2x^2 - x^2 = x^2 (first term);
3x - 5x = -2x (second term);
-7 - 39 = -46 (third term)
Then we have, all on the left side, x^2 - 2x - 46, which is a quadratic equation. Here the coefficients are a = 1, b = -2 and c = -46.
Then the discriminant, b^2 - 4ac, is:
(-2)^2 - 4(1)(-46) = 4 + 184.
The roots are:
-(-2) ±√188 2 ± √4√47
------------------- = -------------------
2 2
= 1 ± √47 (last of the answer choices)
=
x = ------------------