1) \(x^{2} +2x-10=0\)
a=1
b=2
c=-10
\(x= \frac{-(2) +or- \sqrt{ 2^{2}+4(1)(-10) } }{2(1)}\)
\(x= \frac{-2 + or - \sqrt{4+40} }{2}\)
\(x= \frac{-2 +or- \sqrt{44} }{2}\)
\(x= \frac{-2+or- 2\sqrt{11} }{2}\)
\(x= -1+or- \sqrt{11}\)
\(\sqrt{11}=3.32\)
-1+3.32 = 2.32
-1-3.32 = -4.32
2) \(x^{2} -2x-9=0\)
a=1
b=-2
c=-9
\(x= \frac{-(-2)+or- \sqrt{ (-2)^{2}+4(1)(-9) } }{2(1)}\)
\(x= \frac{2+or- \sqrt{4+36} }{2}\)
\(x= \frac{2+or- \sqrt{40} }{2}\)
\(x= \frac{2+or-2 \sqrt{10} }{2}\)
\(x=1+or- \sqrt{10}\)
\(\sqrt{10} =3.16\)
1+3.16 = 4.16
1-3.16 = -2.16
3) \(x^{2} -9x+5=0\)
a=1
b=-9
c=5
\(x= \frac{-(-9)+or- \sqrt{(-9)^{2}-4(1)(5) } }{2}\)
\(x= \frac{9+or- \sqrt{81-20} }{2}\)
\(x= \frac{9+or- \sqrt{61} }{2}\)
\(x= \frac{9}{2} +or- \frac{ \sqrt{61} }{2}\)
\(\sqrt{61} = 7.81\)
\(\frac{7.81}{2} =3.91\)
\(\frac{9}{2}=4.5\)
4.5+3.91 = 8.41
4.5-3.91 = 0.59
