SOLUTION: Solve 5x+4y=12 and 3x+4y=4 by substitution? enter your answer as (_,_) please? I already did this much solved the first expression and ended up with: y= 1-3x but now I'

Algebra ->  Expressions-with-variables -> SOLUTION: Solve 5x+4y=12 and 3x+4y=4 by substitution? enter your answer as (_,_) please? I already did this much solved the first expression and ended up with: y= 1-3x but now I'      Log On


   

Question 742022: Solve 5x+4y=12 and 3x+4y=4 by substitution?
enter your answer as (_,_) please?
I already did this much solved the first expression and ended up with:
y= 1-3x
but now I'm stuck! please help me!
Found 2 solutions by mananth, josgarithmetic:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
5x+4y=12

3x+4y=4
4y=4-3x
substitute 4y in first equation
5x+4-3x=12
2x=8
x=4
so y=-2
(4,-2)

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Solve 5x+4y=12 and 3x+4y=4 by substitution?

From the "4" equation,
4y=4-3x
4y%281%2F4%29=4%281%2F4%29-3%281%2F4%29x
y=1-%283%2F4%29x

Using the "12" equation,
5x%2B4%28y%29=12
SUBSTITUTE FOR y found in "4" equation...
5x%2B4%281-%283%2F4%29x%29=12
5x%2B4-3x=12
.
Can you continue with this from there?
TRY ON YOUR OWN FIRST, AND THEN IF YOU NEED....




5x%2B4-3x=12
5x-3x%2B4=12
2x=12-4
2x=8
highlight%28x=4%29.

Back to the y from the "4" equation,
y=1-%283%2F4%29x
y=1-%283%2F4%29%284%29=1-3=-2
highlight%28y=-2%29