Matt's Magical Math
 
 

This wonderful web page is for all of the math students around the world.  This web page is designed to help the problems anyone might have with Systems of Equations.
Subsitution Method
 Ex.  x-5y=10     x-5(2x+7)=10           Y=2(-5)+7
        y=2x+7       x-10x-35=10                  -10+7
                            -9x-35=10     p;          Y=-3
                                  +35=10
                                -9x=45
                                   -9   -9 
                             X=-5
The method you are going to use to solve these problems is the subsitution method.  What you are you trying to do is get a equation in Y intercept form.  First you want to subsitute the Y in the first equation X-5y=10, with the second equation Y=2x+7, because Y is given. Simpily work equation and you end up with -9x=45, then divide to come up with your answer, which is x=-5.  To find Y just plug in X in the Y equation.  Your ending answer would be X=-5, and y=-3

 
         Elimination Method

     Ex.   -5(x+2y=6)                 x+2y=6
                 5x+3y=2               x+(2)4=6
            -5x+10y=-30    &nbbsp;         x + 8  =6
                5x + 3y= 2                    -8  -8
                      7y=28                    X = -2
                       7     7
                     Y= 4
 
 
 
 

 In order to solve this problem you're going to use the elimination method.  In order to solve these equations you are trying to cancel out either the "x" or the "y" in one of the equations so in order to do so you must multiply top equation by -5, that will make equations -5x+10=-30 and 5x+3y=2.  Now you will just solve the equations.  When you get the y value plug it into the other equation.