## 17Calculus Precalculus - Use Graphing to Solve Systems of Linear Equations

##### 17Calculus

Solve by Graphing

If you have only two equations and two unknowns, graphing can sometimes be used to solve the system of equations. We say 'sometimes' since this technique is not very exact and works only if you can graph very, very accurately and read the graph accurately. But for starters it is good to learn to do this to get a feel for what you are actually doing with the equations.
Here is a good video to get you started. He explains how to solve by graphing while doing an example. He also shows how to check your answer, an important step when working these kinds of problems.

### Khan Academy - Graphing Systems of Equations [6min-34secs]

Okay, let's work some practice problems before we go on.

Practice

Unless otherwise instructed, solve these linear systems by graphing.

$$5x-y=6$$
$$2x+y=8$$

Problem Statement

$$5x-y=6$$
$$2x+y=8$$

Solution

### PatrickJMT - 1705 video solution

video by PatrickJMT

Log in to rate this practice problem and to see it's current rating.

$$y=-2x+2$$
$$y=-6x-2$$

Problem Statement

$$y=-2x+2$$
$$y=-6x-2$$

Solution

### MIP4U - 1706 video solution

video by MIP4U

Log in to rate this practice problem and to see it's current rating.

$$y=-x+3$$
$$2x-2y=10$$

Problem Statement

$$y=-x+3$$
$$2x-2y=10$$

Solution

### MIP4U - 1708 video solution

video by MIP4U

Log in to rate this practice problem and to see it's current rating.

$$2x+y=4$$
$$y=-2x-5$$

Problem Statement

$$2x+y=4$$
$$y=-2x-5$$

Solution

### MIP4U - 1709 video solution

video by MIP4U

Log in to rate this practice problem and to see it's current rating.

$$y=x+3$$
$$y=-x+3$$

Problem Statement

$$y=x+3$$
$$y=-x+3$$

Solution

### Khan Academy - 2128 video solution

Log in to rate this practice problem and to see it's current rating.

$$y=3x-6$$
$$y=-x+6$$

Problem Statement

$$y=3x-6$$
$$y=-x+6$$

Solution

Log in to rate this practice problem and to see it's current rating.

When using the material on this site, check with your instructor to see what they require. Their requirements come first, so make sure your notation and work follow their specifications.

DISCLAIMER - 17Calculus owners and contributors are not responsible for how the material, videos, practice problems, exams, links or anything on this site are used or how they affect the grades or projects of any individual or organization. We have worked, to the best of our ability, to ensure accurate and correct information on each page and solutions to practice problems and exams. However, we do not guarantee 100% accuracy. It is each individual's responsibility to verify correctness and to determine what different instructors and organizations expect. How each person chooses to use the material on this site is up to that person as well as the responsibility for how it impacts grades, projects and understanding of calculus, math or any other subject. In short, use this site wisely by questioning and verifying everything. If you see something that is incorrect, contact us right away so that we can correct it.