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Question 69430This question is from textbook Beginning Algebra
: plotting ordered pairs so that each is a solution for the given equation:
This is my problem 3x+4y=12 (0, ) ( ,3/4) ( ,0) (8/3, ) I have spent about 4 hours working on this. I tried solving for both x and y then plugging the number in. That didnt work out. I have tried graphing it to see if I could make more sense out of it that way, and that didnt help me much, and I believe it confused me worse. PLease Help!!
This question is from textbook Beginning Algebra
Found 2 solutions by stanbon, tutorcecilia:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! This is my problem 3x+4y=12 (0, ) ( ,3/4) ( ,0) (8/3, )
If x=0, you get 0+4y=12; y=3. So the point is (0,3)
If x=8/3, you get 3(8/3)+4y=12; 8+4y=12; 4y=4; y=1. So the point is (8/3,1)
If y=3/4, you get 3x+4(3/4)=12; 3x+3=12; 3x=9; x=3. So the point is (3,3/4)
If y=0, you get 3x+0 = 12; x=4. So the point is (4,0)
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Cheers,
Stan H.
Answer by tutorcecilia(2152)  (Show Source):
You can put this solution on YOUR website! 3x+4y=12 [solve for y]
3x-3x+4y=-3x+12
4y=-3x+12
4y/4=-3x/4+12/4
y=-3/4x+3 [this is the equation of the line. from here, plug-in the known variable and solve for the missing variable]
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y=-3/4x+3 (let x=0 and solve for y]
y=-3/4(0)+3
y=0+3
y=3
(0,3)
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y=-3/4x+3 (let y=3/4 and solve for x]
3/4=-3/4x+3
3/4-3=-3/4x+3-3
-9/4=-3/4x
(-9/4)(-4/3)=x
3=x
(3, 3/4)
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y=-3/4x+3 (let y=0 and solve for x]
0=-3/4x+3
-3=-3/4x
(-4/3)(-3/1)=-3/4x(-4/3)
4=x
(4,0)
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y=-3/4x+3 (let x=8/3 and solve for y]
y=-3/4(8/3)+3
y=-2+3
y=1
(8/3, 1)
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