How do you solve $2x – 2y = 2$ , $y = 3x – 17$ using substitution?

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Answer 1 · 2016-03-15T00:43:03

This is very simple to do since a variable is already isolated, which is what is necessary to solve a system by substitution.

$2x - 2y = 2 -> y = 3x - 17$

$2x - 2(3x - 17) = 2$

$2x - 6x + 34 = 2$

$-4x = -32$

$x = 8$

Now, substituting 8 for x, we get:

$y = 3(8) - 17$

$y = 24 - 17$

$y = 7$

Thus, the solution set is ${8, 7}$ . Remember: solution sets must always be presented in the form ${x, y}$ !

Practice exercises:

Solve the following by substitution. Leave answers in fractional form when necessary.

a) $x + 2y = -4, 2x - 5y = 6$

b) $2x + 7y = 11, -6x + 3y = 14$

Good luck!

How do you solve 2x – 2y = 22x – 2y = 2, y = 3x – 17y = 3x – 17 using substitution?