Question 59729: how do u graph x+y=3
5x-2y=10
y=1/2x-3
y=x/4+1
x=2
y=-7/2
Answer by checkley71(8403)   (Show Source):
You can put this solution on YOUR website! I'LL HELP YOU WITH THE FIRST 3 THEN YOU'RE ON YOUR OWN.
X+Y=3
Y=-X+3 THIS LINE HAS A SLOPE (m) OF -1 & THE Y INTERCEPT IS 3.
SETTING Y=0 WE GET THE X INTERCEPT IN THE EQUATION Y=mX+b
0=-X+3
-X=-3
X=3 NOW WE HAVE 2 POINTS (0,3) & (-3,0) AND THE SLOPE OF -1.
PLOT THESE 2 POINTS (0,3)(-3,0)AND YOPU HAVE A LINE WITH A SLOPE OF -1.
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5X-2Y=10
-2Y=-5X+10
Y=-5X/-2+10/-2
Y=2.5X-5 NOW WE HAVE SLOPE OF 2.5 AND THE Y INTERCEPT OF -5 (0,-5)
SETTING Y=0 WE SOLVE FOR THE X VALUE
0=2.5X-5
2.5X=5
X=5/2.5
X=2 OR THE POINT (2,0) ALONG WITH THE POINT(0,-5) & A SLOPE OF 2.5 WE PLOT THESE 2 POINTS & DRAW A LINE THROUGH THEM WITH A SLOPE OF 2.5.
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Y=1/2X-3 THIS LINE HAS A SLOPE OF 1/5 OR 0.5 & A Y INTERCEPT OF -3 (0,-3)
NOW WE SET Y=O & SOLVE FOR X
0=1/2X-3
1/2X=3
X=3/(1/2)
X=3*2
X=6 NOW WE HAVE 2 POINTS (0,-3)(6,0) & A SLOPE OF 0.5.
PLOT THESE 2 POINTS (0,-3)(6,0) & DRAW LINE THROUGH THEM WITH A SLOPE OF 0.5.
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HAPPY CALCULATING :)
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