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Question 705639: Hi, i would like some help on this Linear equation:
-3x-3y=3
y=-5x-17
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My answer ended up being (-4,5), but my friend says the answer is (-4,3). We are both terribly confused ! When we check the equation both answers are correct.
-Thank you
Found 2 solutions by rfer, josgarithmetic:
Answer by rfer(16322)   (Show Source):
You can put this solution on YOUR website! y=-5x-17
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-3x-3y=3
-3x-3(-5x-17)=3
-3x+15x+51=3
12x=3-51
12x=-48
x=-4
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-3*-4-3y=3
12-3y=3
-3y=3-12
-3y=-9
y=3
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(-4,3)
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3=5*-4-17
3=20-17
3=3
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5=-5x-17
5+17=-5x
22=-5x
22/-5=x
x=-4.4
Sorry, (-4,5) does not work
Answer by josgarithmetic(39620) (Show Source):
You can put this solution on YOUR website! The -3 equation transforms easily to x+y=-1, and the "17" equation becomes -5x-y=17.
Summary of System:
-5x-y=17
x+y=-1
Add both equations: -4x+0=16; therefore, x=-4.
Substitute the value into either equation.
-4+y=-1
y=+4-1
y=+3
Answer: point (-4,3)
When you check, you found both answers as correct?
Let's try the other point you or the friend found, (-4,5):
-5*(-4)-(5)=17?
20-5=17?
15=17? NO.
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