SOLUTION: i don't understand what to do with these two equations x+y=-1 and 2x-y=7 the directions say Estimate the solution of the linear system graphically. then check the solution algebrai

Algebra ->  Linear-equations -> SOLUTION: i don't understand what to do with these two equations x+y=-1 and 2x-y=7 the directions say Estimate the solution of the linear system graphically. then check the solution algebrai      Log On


   

Question 83179: i don't understand what to do with these two equations x+y=-1 and 2x-y=7 the directions say Estimate the solution of the linear system graphically. then check the solution algebraically.
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
X+Y=-1, Y=-X-1 (RED LINE)
2X-Y=7, -Y=-2X+7, Y=2X-7 (GREEN LINE)
NOW SOLVE THESE 2 EQUATIONS BY SUBSTITUTING (-X-1) FOR Y IN THE SECOND EQUATION & SOLVE FOR X
2X-(-X-1)=7
2X+X+1=7
3X=7-1
3X=6
X=6/3
X=2 ANSWER.
2+Y=-1
Y=-1-2
Y=-3 ANSWER.
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+y+=+-x+-1%2C+y+=+2x+-7%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = -x -1 and y = 2x -7).