SOLUTION: please help help me with this question....Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.... -8

Algebra ->  Graphs -> SOLUTION: please help help me with this question....Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.... -8      Log On


   



Question 490885: please help help me with this question....Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.... -8x -4y=-68
x+3y=16 please help me with this asap i am not sure how to do this and cannot find a similar one to go by i need to get it back to my instructor today

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
-8x - 4y = -68
divide both sides by -4, then you have
2x + y = 17
:
x + 3y = 16
Arrange this equation for substitution
x = -3y + 16
:
Replace x in the 1st simplified equation with (-3y+16)
2(-3y+16) + y = 17
-6y + 32 + y = 17
-6y + y = 17 - 32
-5y = -15
multiply both sides by -1
5y = 15
y = 15/5
y = 3
:
find x
x = -3y + 16
replace y with 3
x = -3(3) + 16
x = -9 + 16
x = 7
:
summarize x=7, y=3
:
:
Check in the 1st original equation
-8x - 4y = -68
-8(7) - 4(3) = -68
-56 - 12 = -68, confirms our solutions