A quadratic equation is given by three parameters:
[tex]ax^2+bx+c=0[/tex]
- a is the quadratic coefficient, since it multiplies [tex]x^2[/tex]
- b is the linear coefficient, since it multiplies [tex]x[/tex]
- c is the numeric coefficient, since it's a pure number.
The quadratic formula states that the two (possible) solutions for a quadratic equation are
[tex]ax^2+bx+c=0 \iff x_{1,2} = \dfrac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]
In your case, you have
[tex]a=8,\quad b=-10,\quad c=-1[/tex]
So, your quadratic equation and its solving formula become
[tex]8x^2-10x-1=0 \iff x_{1,2} = \dfrac{10\pm\sqrt{100+32}}{16}=\dfrac{10\pm\sqrt{132}}{16}[/tex]
