facotr
ax^2+bx+c=0
find what 2 number multiply to c and add to b
what 2 numbers multiply to 6 and add to 5
2 and 3
(x+2)(x+3)=0
set to zero
x+2=0
x=-2
x+3=0
x=-3
x=-2 or -3
other one
for ax^2+bx+c=0
x=[tex] \frac{-b+/- \sqrt{b^{2}-4ac} }{2a} [/tex]
we are given
x^2+7x+11=0
a=1
b=7
c=11
sub
x=[tex] \frac{-7+/- \sqrt{7^{2}-4(1)(11)} }{2(1)} [/tex]
x=[tex] \frac{-7+/- \sqrt{49-44} }{2} [/tex]
x=[tex] \frac{-7+/- \sqrt{5} }{2} [/tex]
x=[tex] \frac{-7+ \sqrt{5} }{2} [/tex] or [tex] \frac{-7- \sqrt{5} }{2} [/tex]
