Question

Solve the following system by graphing. If there​ isn't a unique solution to the​ system, state the reason. y=-2x y=2x+4

Answer 1

We have the system of equations:

y = -2*x

y = 2*x + 4.

To solve it by graphing, you need to graph both lines and see in which point the lines intersect each other.

You can see it in the image below. (blue is y = 2*x + 4, and green is y = -2*x)

We also can calculate the solution with math, let's do that:

y = -2*x

y = 2*x + 4.

We can replace the first equation in the second one, to get:

-2*x = 2*x + 4

Now let's solve this for x

-2*x -2*x = 4

-4*x = 4

x = 4/-4 = -1

Evaluating this in one of the equations we get:

y = -2*-1 = 2

Then the solution is the point (-1, 2), exactly what we can see in the graph.