Question

Solve `y=.13x^2+20.93x+838.43`?

Answer 1

See below:

Explanation:

I'll assume `y=.13x^2+20.93x+838.43` is meant.

Let's use the quadratic formula:

`x = (-b \pm sqrt(b^2-4ac)) / (2a)`

where we have `a=.13, b=20.93, c=838.43`

`x = (-20.93 \pm sqrt((20.93)^2-4(.13)(838.43))) / (2(.13))`

`x = (-20.93 \pm sqrt(438.0649-435.9836)) / .26`

`x = (-20.93 \pm sqrt(2.0813)) / .26`

`x=(-20.93 + sqrt(2.0813)) / .26 ~=-74.95`

`x=(-20.93 - sqrt(2.0813)) / .26 ~=-86.05`

The graph looks like this:

graph{.13x^2+20.93x+838.43[-90,-70,-5,5]}