Question

The axis of symmetry for a quadratic equation can be found using the formula x=-b/2a where a and b are coefficients in the quadratic equation and x represents the values along a vertical line on the coordinate plane.

What is the equation when solved for a?
a=b/2x
a=-b/2x
a=1/2bx
a=-1/2bx

Answer 1

`a=(-b)/(2x)`

or

`a=(-1)/(2)(b)/(x)`

(Disclaimer: I can't tell what your choices really say because I'm not sure what is the denominator. Example does a=-b/2x mean a=-b/(2x) or a=-b/2 x?

Explanation:

`x=(-b)/(2a)`

First I'm going to write
`x` as a fraction because I think it might be more clear what to do then.

`(x)/(1)=(-b)/(2a)`

I'm going to cross-multiply now:

`(2a)(x)=(-b)(1)`

`2ax=-b`

Divide both sides by
`2x`:

`a=(-b)/(2x)`

or

`a=(-1)/(2)(b)/(x)`

Answer 2

a=-b/2x

Explanation:

Simply solve for a in the equation they give you:

1) Multiply by "a" both sides of the equation to remove "a" from the denominator and place it on the left of the equal sign.

2) Then divide both sides of the equation by "x" to remove it from the left, and isolate the value "a" for which you want to solve:

`x=-(b)/(2a) \\a*x=-(b)/(2a) * a\\ax= -(b)/(2) \\a(x)/(x) = -(b)/(2x) \\a=- (b)/(2a)`