SOLUTION: PLease help to solve 3/5x - 1/4y = 7 0.08x + 0.05y = 1.6

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Question 66336This question is from textbook An Incremental Development
: PLease help to solve
3/5x - 1/4y = 7
0.08x + 0.05y = 1.6 This question is from textbook An Incremental Development

Found 2 solutions by stanbon, checkley71:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
1st Equation: 3/5x - 1/4y = 7
2nd Equation: 0.08x + 0.05y = 1.6
Multiply 1st thru by 20; Multiply 2nd thru by 100
3rd: 12x-5y=140
4th: 8x +5y=160
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Add 3rd and 4th to get:
20x=300
x=15
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Substitute x=15 into 1st (or 2nd) to solve for y, as follows:
(3/5)(15) - (1/4)y=7
9 -(1/4)y = 7
-1/4 y=-2
y=8
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Solution: x=15, y=8
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You could check this in 2nd.
Cheers,
Stan H.

Answer by checkley71(8403) (Show Source):
You can put this solution on YOUR website!
3X/5-Y/4=7
.6X-.25Y=7
.08X+.05Y=1.6 MULTIPLY THIS EQUATION BY 5 & ADD
.4X+.25Y=8
.6X-.25Y=7
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X=15 SOLUTION NOW SUBSTITUTE 15 FOR X & SOLVE FOR Y
.6*15-.25Y=7
9-.25Y=7
-.25Y=7-9
-.25Y=-2
Y=-2/-.25
Y=8 SOLUTION
PROOF
.08*15+.05*8=1.6
1.2+.4=1.6
1.6=1.6