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]

video by Khan Academy

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

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

Problem Statement

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

Solution

MIP4U - 1706 video solution

video by MIP4U

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

Problem Statement

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

Solution

MIP4U - 1708 video solution

video by MIP4U

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

Problem Statement

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

Solution

MIP4U - 1709 video solution

video by MIP4U

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

Problem Statement

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

Solution

Khan Academy - 2128 video solution

video by Khan Academy

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

Problem Statement

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

Solution

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