Question

Which are the solutions of x2 = –7x – 8?

Answer 1

You can start by rewriting the equation so that the right side equals zero. Add $-7x$ and $8$ to both sides.

$x^2+7x+8=0$

You can now use the quadratic equation (below), where $a=1, b=7,$ and $c=8$, to find solutions. Plug in these values for $a, b,$ and $c$ into the equation and simplify.

$\frac{-b \pm \sqrt{b^2-4(ac)}} {2a}$
$\frac{-7 \pm \sqrt{7^2-4(1 \times 8)}} {2 \times 1}$
$\frac{-7 \pm \sqrt{49-32}} {2}$
$\frac{-7 \pm \sqrt{17}} {2}$

The final answer is the combination of both solutions.
$x=\frac{-7}{2} \pm \frac{\sqrt{17}} {2} \approx -3.5 \pm 2.06.$

Or approximately...
$x=(-3.5-2.06) \approx -5.56, (-3.5+2.06) \approx-1.44$

Answer 2

X^2 = -7x -8

x^2 +7x +8 = 0

D = 49 -32 = 17

x_1,2 = (-7+/-sqrt17)/2 = (-7-sqrt17)/2 and (-7+sqrt17)/2

hope this will help you