SOLUTION: 49. 9x-12y=18 2y=-x+1 47. X+Y=1 0.75X+0.5Y=2.21 When I tried to solve 47 according to the book my calulations are wrong the book ans is 6.84,-5.84 and for 49 th

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: 49. 9x-12y=18 2y=-x+1 47. X+Y=1 0.75X+0.5Y=2.21 When I tried to solve 47 according to the book my calulations are wrong the book ans is 6.84,-5.84 and for 49 th      Log On


   

Question 62820This question is from textbook beginning algebra
: 49. 9x-12y=18
2y=-x+1
47. X+Y=1
0.75X+0.5Y=2.21
When I tried to solve 47 according to the book my calulations are wrong the book ans is 6.84,-5.84 and for 49 the book ans is (8/5,-3/10 from both of these equation I got different ans. can you help me!! This question is from textbook beginning algebra

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
47) X+Y=1 THEN X=1-Y NOW SUBSTITUTE (1-Y) FOR X IN THE OTHER EQUATION THUS
.75(1-Y)+.5Y=2.21
.75-.75Y+.5Y=2.21
-.75Y+.5Y=2.21-.75
-.25Y=1.46
Y=1.46/-.25
Y=-5.84 SOLUTION.
NOW SUBSTITUTE-5.84 FOR Y AND SOLVE FOR X
X-5.84=1
X=1+5.84
X=6.84 SOLUTION
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49) 2Y=-X+1
X=1-2Y NOW SUB (1-2Y) FOR X IN THE OTHER EQUATION THUS
9(1-2Y)-12Y=18
9-18Y-12Y=18
-30Y=9
Y=9/-30
Y=-3/10 SOLUTION
NO SUB -3/10 FOR Y AND SOLVE FOR X
2*-3/10=-X+1
-6/10=-X+1
X=1+6/10
X=16/10
X=8/5 SOLUTION