add 7x+8 to both sides
x^2+7x+8=0
use quadracit formula
x=[tex] \frac{-b+/- \sqrt{b^2-4ac} }{2a} [/tex]
a=1
b=7
c=8
x=[tex] \frac{-7+/- \sqrt{7^2-4(1)(8)} }{2(1)} [/tex]
x=[tex] \frac{-7+/- \sqrt{49-32} }{2} [/tex]
x=[tex] \frac{-7+/- \sqrt{17} }{2} [/tex]
aprox
x=-5.56155 or -1.438
