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Question 528574: Which equation represents the line with a slope of -1/3 that passes through the point (8,8)?
Answer by lmeeks54(111)   (Show Source):
You can put this solution on YOUR website! The general equation for a straight line is:
y = mx + b
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where m = the slope of the line and b = the y intercept (i.e., where x = 0)
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Recall, slope = rise/run. Positive slope, the line goes up to the right (y gets larger as x gets larger). Negative slope, the line goes down to the right (y gets smaller as x gets larger).
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We are given the slope of - 1/3. A slope = 1 is a 45 deg line. A slope > 1 is a steeper line and a slope <1 is a shallower (flatter) line. In this case, we have a shallow, negative slope (slanting down to the right).
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None of that helps you determine the equation for the line, but it gives you the context for what you expect to find.
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We know three useful things to help solve this problem:
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y = mx + b
m = -1/3
line passes through 8, 8; therefore:
8 = -1/3(8) + b
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add 1/3(8) to both sides so we can solve for b, the y intercept:
8 + 1/3 (8) = b
8 + 8/3 = b
10.67 = b
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put it all together:
y = -0.33x + 10.67
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cheers,
Lee
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