Question

Find the solution to the following by substitution. x + y - 18 y = 3x + 6

Answer 1

(12/5, 15 3/5)

Explanation:

Given: x + y - 18 and y = 3x + 6

Solve for x and y. Start by substituting 3x + 6 for y in the first equation.

We get x + (3x + 6) = 18, which simplifies t x + 4x + 6 = 18, or

5x = 12. Then x must be 12/5.

Substituting 12/5 for x in the first equation, we get 12/5 + y = 18, which simplifies to y = 18 - 12/5, or y = 15.6 or y = 15 3/5.

The solution is then (12/5, 15 3/5).

Answer 2

x=3, y=15. (3, 15).

Explanation:

x+y=18

y=3x+6

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x+(3x+6)=18

x+3x+6=18

4x+6=18

4x=18-6

4x=12

x=12/4

x=3

3+y=18

y=18-3

y=15