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Question 850135: I have this problem I need to figure out and I'm having a problem understanding the example. I need a STEP BY STEP(meaning no steps skipped)to see how the one would arrive at the answer. This is not the actual problem but the example to the problem I need to do. I need to find the answer to both the slope and y-intercept.
Give the slope and y-intercept for the line that passes through (-7,9) and (6,12).
Please explain it as if you were to explain it to a 5 year old.
Found 2 solutions by rothauserc, stanbon:
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! the standard form for a line is y = mx + b where m is the slope and b is the y axis intercept.
the slope is the change in y divided by the change in x
note that we are given two points on the line, so we can calculate the slope
the two points are (-7,9) and (6,12), then
m = (12 - 9) / (6 - -7) = 3/13, therefore
y = (3/13)x + b
now we can substitute for x and y using the point (6,12)
12 = (3/13)*6 + b
12 = 18/13 +b
b = 12 - 18/13 = (156/13) - (18/13) = 138/13
y = (3/13)x + 138/13
the slope is 3/13 and y intercept is 10 8/13
Answer by stanbon(75887)  (Show Source):
You can put this solution on YOUR website! Give the slope and y-intercept for the line that passes
through (-7,9) and (6,12).
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Form: y = mx + b
m is the slope
b is the y-intercept
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slope = (change in y)/(corresponding change in x) = (12-9)/(6--7) = 3/13
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Using x = 6, y = 12, m = 3/13, solve for "b":
12 = (3/13)6 + b
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12 = (18/13) + b
Multiply thru by 13 to get:
13*12 = 18 + 13b
156 = 18 + 13b
Subtract 18 from both sides
13b = 138
Divide both sides by 13 to get:
b = 10.62 when rounded to the hundreth's place
b is the y- intercept
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Cheers,
Stan H.
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