we use quadratic formula for that one
remember that √-1=i
so
for
ax^2+bx+c=0
[tex]x=\frac{-b+/-\sqrt{b^2-4ac}}{2a}[/tex]
so
given
1x^2+5x-5=0
a=1
b=5
c=-5
[tex]x=\frac{-5+/-\sqrt{5^2-4(1)(-5)}}{2(1)}[/tex]
[tex]x=\frac{-5+/-\sqrt{25+20}}{2}[/tex]
[tex]x=\frac{-5+/-\sqrt{45}}{2}[/tex]
[tex]x=\frac{-5+/-3\sqrt{5}}{2}[/tex]
solutions:
[tex]x=\frac{-5+3\sqrt{5}}{2}, \frac{-5-3\sqrt{5}}{2}[/tex]
