Question 81324This question is from textbook
: 4x-3y=33
x=-4y-25
This question is from textbook
Answer by praseenakos@yahoo.com(507)   (Show Source):
You can put this solution on YOUR website! QUESTION:
4x-3y=33
x=-4y-25
ANSWER:
4x-3y=33------------------(1)
The second equation,x=-4y-25 can be written as,
x=-4y-25
==> x + 4y = -25 ----------------(2)
Multiply equation(2) with 4 so that coefficient of becoma same in both the equations(You can make coeffeicient of y same and can follow the following procedure.)
==> 4(x + 4y ) = 4* -25
==> 4x + 16y = -100 ----------------------(3)
Now we have,
4x - 3y = 33------------------(1)
4x + 16y = -100 ----------------------(3)
Subtract (3) from (1)
==> 4x - 3y - ( 4x + 16y ) = 33 - (-100)
==> 4x - 3y - 4x - 16y = 33 + 100
==> -19y = 133
Divide both sides by -19
==> -19y/-19 = 133/-19
==> y = -7
Now substitute this value in any of the given equations.....
Lets take (1)
==> 4x - 3 (-7) =33
==> 4x + 21 = 33
Subtract 21 from both sides....
4x + 21 -21 = 33 - 21
==> 4x = 12
Divide both sides by 4
==> 4x/4 = 12/4
==> x = 3
so the solution is,
x = 3 and y = -7
Hope you found this method useful.
Regards.
Praseena.
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