How do I use a graph to solve the system of equations 3x+4y=103x+4y=10 and x−y=1xy=1?

1 Answer
Jul 9, 2015

You graph the equations and see where they intersect.

Explanation:

Your equations are

3x+4y = 103x+4y=10
x-y = 1xy=1

Let's rearrange these to

(1) y = 1/4(10-3x) = -3/4 x + 5/2y=14(103x)=34x+52
(2) y = x-1y=x1

Plot the graph of Equation 1.

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Now add the graph for Equation 2.

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The two lines intersect at (2,12,1).

The solution is x = 2x=2, y = 1y=1.

Check:

3x+4y = 3×2+4×1 = 6+4 = 103x+4y=3×2+4×1=6+4=10

x-y = 2-1 = 1xy=21=1