SOLUTION: Please help me with this problem: Find all solutions of the given system of equations and check your answer graphically. If the system is dependent, express your answer in term

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Question 793217: Please help me with this problem:
Find all solutions of the given system of equations and check your answer graphically. If the system is dependent, express your answer in terms of x, where y = y(x).)
0.3x + 0.1y = 0.7
0.4x − 0.4y = 1.2
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
I would first multiply both sides of the equal sign times 10 (in both equations) to get
system%283x%2By=7%2C4x-4y=12%29
The second equation can be simplified by dividing both sides by 4 to get
x-y=3
3x%2By=7-->y=7-3x and substituting into x-y=3 we get
x-%287-3x%29=3-->x-7%2B3x=3-->x%2Bx=3%2B7-->2x=10-->x=10%2F2-->highlight%28x=5%2F2%29
Then substituting into y=7-3x, we get
y=7-3%2A%285%2F2%29-->y=7-15%2F2-->y=14%2F2-15%2F2-->highlight%28y=-1%2F2%29

3x%2By=7-->y=7-3x goes through the points
(0,7) because x=0 means y=7-3%2A0=7-0=7 and
(3,-2) because x=3 means y=7-3%2A3=7-9=-2
x-y=3 goes through the points
(0,-3) because x=0 means 0-y=-3-->-y=-3-->y=3 and
(3,0) because y=0 means x-0=3-->x=3
Plotting the two points found for each line and connecting then, we get