# SOLUTION: I'm not really clear on how to set up this type of problem. Any insight would be greatly appreciated. x+y=12 y=3x

Algebra ->  Algebra  -> Coordinate Systems and Linear Equations -> SOLUTION: I'm not really clear on how to set up this type of problem. Any insight would be greatly appreciated. x+y=12 y=3x      Log On

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 Question 107332This question is from textbook Introductory and Intermediate Algebra : I'm not really clear on how to set up this type of problem. Any insight would be greatly appreciated. x+y=12 y=3xThis question is from textbook Introductory and Intermediate Algebra Found 2 solutions by ptaylor, Fombitz:Answer by ptaylor(2048)   (Show Source): You can put this solution on YOUR website!x+y=12-------------------eq1 y=3x----------------------eq2 I think that substituting "y=3x" from eq2 into eq1 is the easiest way to work this problem. If we do that, we get: x+3x=12 or 4x=12 divide both sides by 4 x=3 From eq2: y=3x=3*3=9 So: x=3 and y=9 We could also subtract eq2 from eq1 and we would get: x=12-3x add 3x to both sides x+3x=12-3x+3x or 4x=12 same as before CK from eq1 x+y=12 3+9=12 12=12 from eq2 y=3x 9=3*3 9=9 Hope this helps----ptaylor Answer by Fombitz(13828)   (Show Source): You can put this solution on YOUR website!1. 2. You have two equations with two unknowns, a linear system of equations. You should be able to solve for x and y. Using equation 2 and substitute into equation 1. 1. Now substitute into 2. 2. Check your answers with your original equations. 1. True statement. Good answer. 2. True statement. Good answer. x=3 and y=9.