Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth. x^2-21=-4x

Answer 1

We rewrite the equation in standard form: x^2 + 4x - 21 = 0.

We can now use the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / 2a

where a = 1, b = 4, and c = -21.

Substituting these values, we get:

x = (-4 ± √(4^2 - 4(1)(-21))) / 2(1)

x = (-4 ± √(16 + 84)) / 2

x = (-4 ± √100) / 2

We simplify the square root:

x = (-4 ± 10) / 2

There are two solutions:

x = (-4 + 10) / 2 = 3

x = (-4 - 10) / 2 = -7

Therefore, the solutions are x = 3 and x = -7.