Question 155953: 0.3x-0.2y=4
0.2x+0.5y=-3
Answer by Electrified_Levi(103)   (Show Source):
You can put this solution on YOUR website! Hi, Hope I can help
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If you are trying to find the solution to the two equations, this is the way I do it.
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First, we will multiply each equation by 10(multiply each side of the two equations by 10)(you don't have to, but it will get rid of the decimal point)
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We will multiply
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First equation = =  = 
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Second equation =  =  = 
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The two new equations  are
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First equation =
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Second equation =
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Now we can start solving
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First, solve for a letter in each equation(doesn't matter which letter) we will solve for "x"
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First equation =
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We will move (-2y) to the right side
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 = 
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We will rearrange the right side
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= 
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We will divide by "3" to get "x"
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 = 
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Our first answer = 
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Now we will solve our second equation
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We will move "5y" to the right side
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 = 
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If we rearrange we will get 
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We need to divide by "2" to get "x"
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 = 
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Our second answer = 
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Our two answers we got are
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Answer 1 =
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Answer 2 =
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We will now put the two answers together in an equation (since they equal the same letter "x", they equal each other)
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Now we will start solving for "y", we will cross multiply
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we will get 
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when we use distribution, we get 
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We will move (-15y) to the left
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 = 
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We will move the "80" to the right
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 = 
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We will now divide each side by "19" to get "y"
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 = 
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We found that "y" = 
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We can replace "y" with in one of our easier equations( one of the  equations
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We will use the first equation(replace "y" with
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double negative
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we will move  to the right side
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 = 
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we need to change the "40" , 40 =  , replace "40" with that number
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 = 
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No we will divide each side by "3" to get our answer
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 =  = 
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Our "x" =  , we can check our solution in one of our original equations(our very first two equations)
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Equation 1 =
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Equation 2 =
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"x" =
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"y" =
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We will replace "x" and "y"
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Equation 1 =  ( 0.3 same as  )(0.2 same as 
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 = 
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 (True)
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We can replace "x" and "y" in our second equation ( 0.2 =  , 0.5 =  =  ) ( we will use )
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 =  True
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"x" = or 7 
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"y" = or ( -8  )
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solution set = (x,y), our solution set = (, )
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Hope I helped,Levi
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