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Question 562497: x=16-4y
3x+4y=8
Answer by MathHelper7(6)   (Show Source):
You can put this solution on YOUR website! x=16-4y
3x+4y=8
Pretty simple.
x=16-4y is already in mx+b form. You'll need to get the other in mx+b form.
3x+4y=8
-3x -3x ; Minus 3x by both sides, it then becomes -3x but on the other side:
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4y=-3x+8
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4 4 ; Divide 4 by both sides so y is by itself, divide 4 by mx+b
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y=-¾x+2 ; Since -3 doesn't go into 4 evenly, then it becomes a fraction.
Slope CAN be a fraction.
Now for the other.
x=16-4y
+4y +4y ; Add 4y by both sides, because 4y was a negative before.
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4y+x=16
+-1x +-1x ; Add negative 1x by both sides
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4y=-1x+16
- ----- ; Divide 4 by both sides, divide mx+b by 4
4 4
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y=-1/4x+4 ; The x becomes 1 over 4 or 1/4, so the slope is 1/4x
Now you have both of them in mx+b form!
y=-1/4x+4
y=-¾x+2
If you are graphing, you can graph like this:
For: y=-1/4x+4
Put a dot at 4 on the y-axis because the spot that 4 is in is the y-intercept.
The slope is 1/4, and slope is
1 (Rise)
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4 (Run)
Meaning you go up 1 and over 4, so start at 4 and go up 1 over 4 until you run out of graph to work on, then draw a line on the points.
Same for y=-¾x+2
3 (Rise)
-
4 (Run)
So you go up 3, over 4. Until you run out of graph. Then draw a line.
Hope this helped, sorry for making it so long!
-MathHelper
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