SOLUTION: 33. .2x=.3y-2 1.5y=x+.8 35. 0.5x+2y=1.15 -3x+0.4y=-0.7 I was having some problems with these two equation I know that I have to use 10 and multiply by the decimal

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: 33. .2x=.3y-2 1.5y=x+.8 35. 0.5x+2y=1.15 -3x+0.4y=-0.7 I was having some problems with these two equation I know that I have to use 10 and multiply by the decimal      Log On


   

Question 62571This question is from textbook beginning algebra
: 33. .2x=.3y-2
1.5y=x+.8
35. 0.5x+2y=1.15
-3x+0.4y=-0.7
I was having some problems with these two equation I know that I have to use 10 and multiply by the decimal number but the ans is off or incorrect. Please help me with this step by step. Thanks!!! This question is from textbook beginning algebra

Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
33.
E1: .2x=.3y-2
E2: 1.5y=x+.8
Multiply both E1 and E2 by 10
E1: 10(.2x)=10(.3y-2) ---> 2x=3y-20
E2: 10(1.5y)=10(x+.8) ---> 15y=10x+8
Divide both sides of E1 by 2.
E1: 2x/2=3y/2-20/2 ---> x=(3/2)y-10
Substitute x=(3/2)y-10 in for x in E2 and solve for y.
E2: 15y=10%28%283%2F2%29y-10%29%2B8
15y=5%283y%29-100%2B8
15y=15y-92
15y-15y=15y-15y-92
0=-92
The variable was eliminated and 0 does not = -92, therefore there is no solution. Graphically, these lines are parallel and will never intersect.
:
35.
E1: 0.5x+2y=1.15
E2: -3x+0.4y=-0.7
Multiply E1 by 100 and E2 by 10.
E1: 100(0.5x+2y)=100(1.15) ---> 50x+200y=115
E2: 10(-3x+0.4y)=10(-0.7) ---> -30x+4y=-7
Multiply E2 by -50 and add E1+E2 and the y's are eliminated.
E2: -50(-30x+4y)=-50(-7) --> 1500x-200y=350
:
50x+200y=115
1500x-200y=350
_______________
1550x=465
1550x/1550=465/1550
x=.3
Let x=.3 in the original E1 and solve for y
0.5(.3)+2y=1.15
0.15+2y=1.15
0.15-0.15+2y=1.15-0.15
2y=1
2y/2=1/2
y=.5
The solution is (.3,.5)
Happy Calculating!!!