Question

which equation shows the quadratic formula used correctly to solve 7x^2=9+x for x?

Answer 1

I don't see any equation. However this equation can b written as follows

7x²=9+x
7x² - x - 9 = 0

Answer 2

so first you need to get into form
0=ax²+bx+c
it is prefered that a is positive
so

7x²=9+x
minus (9+x) from both sides
7x²-1x-9=0

a=7
b=-1
c=-9

for 0=ax²+bx+c
$x=\frac{-b+/-\sqrt{b^2-4ac}}{2a}$


so, a=7
b=-1
c=-9

$x=\frac{-(-1)+/-\sqrt{(-1)^2-4(7)(-9)}}{2(7)}$ would be the eqquation
but if you did want to solve
$x=\frac{1+/-\sqrt{253}}{14}$