Question 398222
Q. Solve by graphing: y=-x+2 & 3x+3y=12 
A. She has 12 = -3x+3y & (0,2) as answers and a graph that doesn't look right to me. 
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You can check that answer by letting x = 0 and y = 2
in the two sentences.
You would get:
2 = 0+2 which is ok
You would also get:
3*0+3*2 = 12
0+6 = 12
6 = 12 which is not ok
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Graph each equation by plotting 2 points and drawing a line thru them.
y = -x+2
Let x = 0, then y = 2 giving you point (0,2)
Let x = 1, then y = -1+2 = 1 giving you point (1,1)
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3x+3y=12 
Let x = 0, then 3y= 12, and y = 4 giving you point (0,4)
Let x = 2, then 3*2+3y=12 and 3y = 6 so y = 2 giving you point (2,2)
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{{{graph(400,300,-10,10,-10,10,-x+2,-x+4)}}}
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Do you see there is no solution because the lines are parallel.
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Cheers,
Stan H.