Respuesta :

The equation should be 7x^2 -x-9=0

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.

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