How do you solve the following equations by substitution: 8x - 4y = 16 and y = 2x - 4??

1 Answer
Alan P.
Oct 21, 2015

There are infinitely many solutions to this pair of equations. (See below for demonstration using substitution).

Explanation:

Given:
[1]color(white)("XXX")8x-4y=16
[2]color(white)("XXX")y=2x-4

Substituting (2x-4) from [2] for y in [1]
[3]color(white)("XXX")8x-4(2x-4)=16

Simjplifying
[4]color(white)("XXX")16 = 16

Since this is true for all pairs (x,y) there is no unique solution.
(The equations represent the same line).

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