M8A5(b) Solve systems of equations algebraically

There a different steps to solve equaltions such as elimination and substitution.
Substituion                                                                     Elimination

x +2y = 1                                                                      

2x-y =7 change equation to y-intercept form                   

2x-y =7                        

-2x    -2x

-y = -2x +7

-1       -1

y=2x-7

Now it’s time to substitute

x+ 2(2x-7)=1                   y=2x-7

x+4x-14   =1                    y=2(3)-7

5x-14=1                            y=6-7

  +14   +14                         y=-1

 5x =15

5           5

    x=3    To check just substitute the

              x and y values into the

              equations.

 Elimination

5x +3y =17.22      Chose which value to eliminate                   

5x+3y=17.22                                           

 3(x  - y =.90)                                             

5x+3y=17.22        eliminate the y            

3x –3y=2.70

    8x = 19.92

8                   8

  x =2.49

Solve for y

2.49-y=.90

       +y       +y  

 2.49=.90 +y

  -.90  -.90

   1.59=y

To solve by graph change the equations to slope y intercept form as shown above. Graph the y intercept first then graph the slope until the two lines meet up at one point on the graph.