x^2+5(x+5)=30(x+5)
distribue
x^2+5x+25=30x+150
minus 30x+150 from both sides
x^2-25x-125=0
use quadratic formula
in form
ax^2+bx+c=0
x=[tex] \frac{-b+/- \sqrt{b^2-4ac} }{2a} [/tex]
a=1
b=-25
c-125
x=[tex] \frac{-(-25)+/- \sqrt{(-25)^2-4(1)(-125)} }{2(1)} [/tex]
x=[tex] \frac{25+/- \sqrt{625+500} }{2} [/tex]
x=[tex] \frac{25+/- \sqrt{1125} }{2} [/tex]
x=[tex] \frac{25+/- 15\sqrt{5} }{2} [/tex]
x=12.5+/- 7.5√5
x=12.5+7√5 or 12.5-7.5√5
no extranious roots seen
