SOLUTION: How would you solve and check each of the following problems using the substition method. First problem: 3x+y=5 -2x+3y=4 Second Problem: y=5x 2x+y=28 Third Problem: x+3

Algebra ->  Expressions-with-variables -> SOLUTION: How would you solve and check each of the following problems using the substition method. First problem: 3x+y=5 -2x+3y=4 Second Problem: y=5x 2x+y=28 Third Problem: x+3      Log On


   

Question 173673: How would you solve and check each of the following problems using the substition method.
First problem:
3x+y=5
-2x+3y=4
Second Problem:
y=5x
2x+y=28
Third Problem:
x+3y=23
3x-2y=3
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

First problem:
3x%2By=5, EQN 1
-2x%2B3y=4, EQN 2
.
I'll do the 1st problem, and take care the rest:
In EQN 1,we isolate "y" and get:
y=-3x%2B5-----> EQN 3, subst. in EQN 2:
-2x%2B3%28highlight%28-3x%2B5%29%29=4
-2x-9x%2B15=4
-11x=4-15=-11
cross%28-11%29x%2Fcross%28-11%29=cross%28-11%291%2Fcross%28-11%291
highlight%28x=1%29, subst. in EQN 3:
y=-3%281%29%2B5=-3%2B5
highlight%28y=2%29
Check, subst "x" & "y" in EQN 2 (or EQN 1):
-2%281%29%2B3%282%29=4
-2%2B6=4
4=4, good
Thank you,
Jojo