SOLUTION: solve the equation by the use of substitution method showing all the steps taken in solving equation; 2/5x + 3/2y = 2 7/3x - 5/4y = -5

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Question 976063: solve the equation by the use of substitution method showing all the steps taken in solving equation;
2/5x + 3/2y = 2
7/3x - 5/4y = -5
Found 2 solutions by FrankM, Edwin McCravy:
Answer by FrankM(1040)   (Show Source): You can put this solution on YOUR website!
2/5 x + 3/2 y = 2
7/3 x - 5/4 y = -5
Multiply the first equation by 10. i.e both sides.
4x + 15y = 20
Multiply the first equation by 12.
28x - 15y = -60
add the 2 equations
32x = -40
x = -1.25 or -5/4
y = 5/3
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
The other tutor didn't use the substitution method but used the 
addition (elimination) method.  Even though it's easier here, one
must follow instructions.  Here's the substitution method:

solve the equation by the use of substitution method showing all the steps taken
in solving equation;


Get rid of the fractions first by muyltiplying the first equation
through by the LCD of 10 and the second one through by the LCD of 12



Solve the first equation for 4x = 20-15y

Then since 28x is 7*4x, replace 28x by 7(20-15y) in the second equation:

      28x-15y = -60
7(20-15y)-15y = -60
 140-105y-15y = -60
     140-120y = -60
        -120y = -200
            y = 5/3

Substitute in 

           4x = 20-15y
           4x = 20-15(5/3)
           4x = 20-25
           4x = -5
            x = -5/4

Edwin
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