SOLUTION: solve using substition method 4x+7y=40; x=28-4y

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Question 185311: solve using substition method 4x+7y=40; x=28-4y
Answer by feliz1965(151)   (Show Source): You can put this solution on YOUR website!
solve using substition method 4x+7y=40; x=28-4y
You are given x to be 28 - 4y.
Plug that value of x into 4x + 7y = 40 and solve for y.
4(28 - 4y) + 7y = 40
112 - 16y + 7y = 40
112 - 9y = 40
-9y = -112 + 40
-9y = -72
y = -72/-9
y = 8
We now know the value of y to be 8.
To find x, plug that value of y into EITHER of the original equations given and solve for x.
I'll let you finish.





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