SOLUTION: Help please. 1. Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this. x + 7y = -2 3x + y = 34

Algebra ->  Coordinate-system -> SOLUTION: Help please. 1. Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this. x + 7y = -2 3x + y = 34       Log On


   

Question 245385: Help please.
1. Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.
x + 7y = -2
3x + y = 34

2. Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this.
-4x + 9y = 20
-2x - 2y = 10

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1.x+%2B+7y+=+-2
2.3x+%2B+y+=+34
From 2,
3x%2By=34
y=34-3x
Substitute into eq. 1,
x%2B7%2834-3x%29=-2
x%2B238-21x=-2
-20x=-240
x=12
From eq. 1,
x%2B7y=-2
12%2B7y=-2
7y=-14
y=-2
(12,-2)
.
.
.
-4x+%2B+9y+=+20
-2x+-+2y+=+10+
Multiply eq. 2 by -2 and add to eq. 1
-4x%2B9y%2B4x%2B4y=20-20
13y=0
y=0
From eq. 2,
-2x-2y=10
-2x=10
x=-5
(-5,0)