SOLUTION: 1. Solve for X and Y in the following problems. Make sure you show all your work so you can get partial credit even if your final answer is wrong. a. X + Y=7 , X + 2Y = 11

Question 151459: 1. Solve for X and Y in the following problems. Make sure you show all your work so you can get partial credit even if your final answer is wrong.
a. X + Y=7 , X + 2Y = 11
b. 3X + 7Y = 24, 9X + 5Y = 24
c. 4X + Y = 17, 2X + 3Y = 21
d. 18X + Y = 42, 6X - 3Y = -6

Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
I'LL DO THE FIRST 2 TO SHOW YOU HOW IT'S DONE.
THE LAST 2 ARE FOR YOU TO PRACTICE WITH NOW THAT YOU HAVE THE PROCEDURE.
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a)X + Y=7
X + 2Y = 11 SUBTRACT.
---------------
-Y=-4
Y=4 ANSWER.
X+4=7
X=7-4
X=3 ANSWER.
PROOF
3+2*4=11
3+8=11
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b)3X + 7Y = 24 MULTIPLY BY -3 & ADD.
9X + 5Y = 24
-9X-21Y=-72 ADD.
---------------
-16Y=-48
Y=-48/-16
Y=3 ANSWER.
9X+5*3=24
9X+15=24
9X=24-15
9X=9
X=9/9
X=1 ANSWER.
PROOF:
3*1+7*3=24
3+21=24
24=24

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