Question 503708: find equation of each line, write in slope interept and standard form (if possible).
1. through (-7,2) and perpendicular to y=2x ???
i got confused on how to find slope if i dont have a "b" for that y=2x equation??
AND ALSO...
2. through (-2,3) and (6,1)
AND ALSO...
3. how do you graph inequalities on a ti86 calculator? shading and all?
Answer by oberobic(2304)   (Show Source):
You can put this solution on YOUR website! A line perpendicular to y = 2x will have slope = -1/2.
y = -1/2x + b
We want it to go through (-7,2), so substitute these values to find 'b'.
2 = -1/2(-7) + b
2 = 7/2 + b
b = -3/2
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y = -1/2x -3/2
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1/2x + y = -3/2
x + 2y = -3 in standard form
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A line passing through (-2,3) and (6,1) can be determined.
m = change in y / change in x
change in y = 1-3 = -2
change in x = 6-(-2) = 8
m = -2/8 = -1/4
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y = -1/4x + b
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substitute a point you know, say (-2,3)
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3 = -1/4*-2 + b
3 = 1/2 + b
2 1/2=b
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y = -1/4x + 2 1/2
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1/4x + y = 5/2
x + 4y = 10 in standard form
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It is better to post new questions than to add them to an existing question. But I'll give these a try.
1. -[2x-(5x+2)] = 2+(2x+7)
HOW DO I DISTRIBUTE WITH THE NEGATIVE OUTSIDE? WHAT DO THE BRACKETS MEAN??
The square brackets are just meant to be distinctive from parentheses. In English we usually have square brackets to enclose parentheses, and curly braces to enclose square brackets. You can replace them with parentheses. But you should always work from the innermost parentheses out.
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Let u = 5x+2 to make is simpler.
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-(2x -u) = -2x -(-u) = -2x +u
So, replace the 'u' with what it means:
-2x + (5x+2)
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-(2x-(5x+2)) = 2+(2x+7)
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-2x +(5x+2) = 2 + (2x+7)
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-2x +5x +2 = 2 + 2x + 7
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3x + 2 = 2x + 9
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x = 7
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2. -[3X-(2X+5)] = -4 -[3(2X-4)-3X]
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-(3x -(2x+5)) = -4 -(3(2x-4)-3x)
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-(3x -2x -5) = -4 -(6x -12 -3x)
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-3x +2x +5 = -4 -(3x -12)
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-x + 5 = -4 -3x + 12
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-x + 5 = -3x + 8
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2x = 3
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x = 3/2
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