Answer:
The equation [tex]x=\frac{-(-1)\pm \sqrt{(-1)^2-4(7)(-9)}}{2(7)}[/tex] shows the quadratic formula used correctly to solve the given equation.
Step-by-step explanation:
If a quadratic equation is defined as [tex]ax^2+bx+c=0[/tex], then the quadratic formula is
[tex]x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}[/tex]
The given equation is
[tex]7x^2=9+x[/tex]
Subtract 9 and x from both the sides.
[tex]7x^2-x-9=0[/tex]
Here, a=7, b=-1 and c=-9.
Substitute a=7, b=-1 and c=-9 in the quadratic formula.
[tex]x=\frac{-(-1)\pm \sqrt{(-1)^2-4(7)(-9)}}{2(7)}[/tex]
Therefore the equation [tex]x=\frac{-(-1)\pm \sqrt{(-1)^2-4(7)(-9)}}{2(7)}[/tex] shows the quadratic formula used correctly to solve the given equation.
