Question

How do you solve the equation `-x^2-7x=0` by graphing?

Answer 1

`x=0` or `x=-7`
`color(white)("XXXXXXX")`see below for solution by graphing.

Explanation:

If you have graphing software (or a graphing calculator) you should be able to generate the graph for `f(x)=-x^2-7x`.
Here is what it looks line with Socratic's Graph utility:
graph{-x^2-7x [-16.02, 12.45, -1.78, 12.44]}
You can see that the graph crosses the X-axis (that is `-x^2-7x=0`) at `x=0` and `x=-7`.