SOLUTION: solve by the subst Solve by the substitution method. 9x+3y=-30 -3x+y=20 What is the solution of the system? The solution is____? (Type an ordered pair)

Algebra ->  Graphs -> SOLUTION: solve by the subst Solve by the substitution method. 9x+3y=-30 -3x+y=20 What is the solution of the system? The solution is____? (Type an ordered pair)       Log On


   

Question 449477: solve by the subst
Solve by the substitution method.
9x+3y=-30
-3x+y=20
What is the solution of the system?
The solution is____?
(Type an ordered pair)

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
9x+3y=-30 .............1
y=20+3x ---------2
/1=
y=20+3x
Plug the value of y in (1)
9x+3(20+3x)=-30
9x+60+9x=-30
9x+9x= -30 -60
18x=-90
/18
x=-5
Plug the value of x in (1)
9x+3y=-30
9*-5+3y=-30
-45+3y=-30
3y=15
/3
y=5
(-5,5)