Solve the equation by completing the square. Round to the nearest tenth.
x^2 + 8x = 10.
To solve this equation by completing the square, first move the constant term to the other side of the equation:
x^2 + 8x = 10
x^2 + 8x - 10 = 0
Next, take half of the coefficient of x (in this case, 8) and square it:
(8/2)^2 = 16
Add this value to both sides of the equation:
x^2 + 8x + 16 = 10 + 16
(x + 4)^2 = 26
Take the square root of both sides:
x + 4 = ±√26
x = -4 ± √26
So the solutions are x ≈ -7.1 or x ≈ -0.9.
What about from the answers,
A: 1.1, 9.1
B: 1.1, -9.1
C: -1.1, 9.1
D: -1.1, -9.1
Calculating the solutions again:
x = -4 ± √26 ≈ -4 ± 5.1
x ≈ -4 + 5.1 = 1.1
x ≈ -4 - 5.1 = -9.1
Therefore, the correct answer is B: 1.1, -9.1.