SOLUTION: Hi. I need help solving this problem for my physics class. I am a bit rusty on solving systems. I need to solve for x and y. 47-x=17y 23y+81=-3x

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Hi. I need help solving this problem for my physics class. I am a bit rusty on solving systems. I need to solve for x and y. 47-x=17y 23y+81=-3x      Log On


   

Question 159428: Hi. I need help solving this problem for my physics class. I am a bit rusty on solving systems.
I need to solve for x and y.
47-x=17y
23y+81=-3x
Found 2 solutions by jojo14344, scott8148:
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

47-x=17y ------------------------------------> eqn 1
23y%2B81=-3x ----------------------------------> eqn 2
In eqn 1, we get
47-17y=x -------------------------------------> eqn 3, subst. in eqn 2
23y%2B81=-3%2847-17y%29
23y%2B81=-141%2B51y combine similar terms
81%2B141=51y-23y
222=28y ------> cross%28222%297.92857%2Fcross%2828%29=+cross%2828%29y%2Fcross%2828%29
y=7.92857
Go back eqn 3:
x=47-17%2A7.92857=47-134.7857
x=-87.7857
In doubt? go back eqn 2:
23%287.92857%29%2B81=-3%28-87.7857%29
182.3571%2B81=263.3571
263.3571=263.3571
Thank you,
Jojo

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
from 1st eqn __ -x=17y-47 __ x=47-17y

substituting into 2nd eqn __ 23y+81=3(17y-47) __ 23y+81=51y-141 __ 222=28y __ 111/14=y

substituting __ x=47-(17(111/14)) __ x=-1229/14