SOLUTION: I have a problem in my math lab that I can not figure out here is what I have so far... Solve by substitution method 3x+8y=18 -5x+y=13 solve for y, Y=13+5x 3x+8(13+5x)=1

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Question 317461: I have a problem in my math lab that I can not figure out here is what I have so far...
Solve by substitution method
3x+8y=18
-5x+y=13
solve for y, Y=13+5x
3x+8(13+5x)=18
remove the parenthesis
3x+104+40x=18
What is the coefficient of x? 43
Now solve for x.
The answer for x is -2 but I do not know how to get this answer can you please show me what i am doing wrong.
The answer I get is this 43x=132
Thank you
Found 2 solutions by Fombitz, JBarnum:
Answer by Fombitz(32388)   (Show Source): You can put this solution on YOUR website!
You added instead of subtracted.
.
.

<--- Subtract 104 from both sides
<--- Divide both sides by 43
Answer by JBarnum(2146)   (Show Source): You can put this solution on YOUR website!
you were right up to this point
3x+104+40x=18
43x+104=18 subtract 104
43x=-86 divide by 43
x=-2
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