First Question:
2x - 3y = 9
By definition, the intercept is where the function intersect with the axis. Therefore, the x-intercept is where the function intersect with the x-axis, and y-intercept is where the function intersect with the y-axis. At the same time, the x-axis is a horizontal line which y = 0; and y-axis is a vertical line which x = 0.
Therefore, to find x -intercept, we substitute y with 0 into the equation; and to find y-intercept, we substitute x = 0 into the equation.
x-intercept:
2x = 9
x = 9/2
y-intercept:
-3y = 9
y =-3
Second Question:
Line parallel means slope is the same, so you need to simply the equation into slope-intercept form first.
y = mx +b
m: slope
b: y-intercept
2y = 4x - 8
y = 2x - 4
A parallel line will have a form:
y = 2x - b
In order to find b, we need to substitute the point into the equation:
5 = 2(1) + b
b = 3
Therefore, the equation for a line parallel to 2y =4x - 8 will be:
y = 2x + 3
[Finished typing the whole thing and fixed some mistakes I made]
2007-05-29 02:03:55
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answer #1
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answered by Ben 3
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The standard form for the equation of a line is y=mx+b where m is the slope and b is the y-intercept.
So, let's take the first equation and put it in this form.
2x-3y=9 so, subtract 2x from each side, and you get:
-3y=-2x+9
Now, divide by -3 on both sides, and you get:
y=(2/3)x-3
So, now you know that the y-intercept is -3. (You can tell this by substituting a 0 for x). Now, to get the x-intercept, set y=0 (i.e., that's where the line crosses the x-axis), and solve for x. So,
0=(2/3)x-3 Add 3 to both sides, and you get:
(2/3)x=3 Multiply by 3 on both sides, and you get:
2x=9 Divide by 2 on both sides, and you get:
x=9/2 That's the x-intercept
As for the second question, the first trick is to figure out the slope. All lines with the same slope are parallel.
So, you have 2y=4x-8
Divide by 2 on both sides, and you get:
y=2x-4 Now you know that the slope of the new line has to be 2 by definintion.
Now, all you need is the y-intercept of the new line. Now, to do that, you have to realize that the slope is defined as the change in x/ change in y.
So, you are looking for y in the point (0,y) -i.e., the y-intercept - for the line with slope 2 that goes through point (1,5)
So, the change in x is 1-0. The change in y is 5-y. So,
(5-y)/1 or 5-y is the slope of the line. So, you get:
5-y = 2 Subtract 5 from both sides, and you get:
-y=-3 or y=3
Now, the equation is y=2x+3
2007-05-29 09:13:21
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answer #2
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answered by RG 3
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The x-intercept as the word suggests, is where the line will cut the x-axis. On the x-axis, the ordinate of the point is 0, so to find x-intercept, substitute y= 0 and solve.
Similarly, the y-intercept is where the line cuts the y-axis, and for that to happen, the x coordinate is 0. So substitute x = 0 to find out.
2)
i) The slope of a line ay= bx + c is given by b/a.
ii) Two lines are parallel if they have the same slope
iii) the equation of a line passing through a point (p,q) is
y-q=m(x-p), where m is the slope.
You now have all the tools to be able to answer your questions, so start.
2007-05-29 09:09:04
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answer #3
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answered by Anonymous
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X intercept is the value of x in equation at y=0. And y-intercept is the value of y in the equation at x=0.
2x-3y=9
x- intercept, let y=0 so x will become x=9/3 this is the x-intercept.
y-intercept, let x=0 so y will become y= -3. This is the y-intercept.
2y=4x-8
The line slope is 4/2 or 2.
Since the unknown line is parallel with the previous line therefore there slope are the same.
Using the equation of the line,
( y-y1)/(x-x1) = slope
x1= 1 , y1=5
Therefore line equation is,
y = 2(x - 1) + 5
2007-05-29 09:18:52
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answer #4
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answered by dongskie mcmelenccx 3
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2x - 3y = 9
x intercept is the value of x when y = 0
y intercept is the value of y when x = 0
x - intercept
2x - 3(0) = 9
x = 4.5
y - intercept
2(0) - 3y = 9
y = -3
Parallel lines have the same slope
we can solve the slope from the eq. 2y = 4x - 8,
convert to std. eq, y = mx + b, where m = slope of the line
y = 2x -4, therefore, m = 2
solving for the eq. of the 2nd line, using the formula for slope
m = (y - y1)/(x - x1), given pt. is (1, 5)
2 = (y - 5)/(x - 1), simplify
2x - 2 = y - 5
2x - y + 3 = 0
2007-05-29 09:12:58
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answer #5
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answered by blitzmonster 2
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y=mx+b is how you get y-intercept
You're problem would be 3y=2x-9 if you subtracted 3y from both sides, and subtracted 9 from both sides.
Then you get y by it's self by dividing both sides by 3. so you have y=2/3x-3
You're slope is 2/3 and you're y-intercept is -3
I'm having a hard time remembering how you find the x-intercept...
but as for your other question you need to change the problem into y=mx+b again to find the slope.
So you would get y=2x-4 so your slope is 2. I can't remember how to get the last part......
Sorry... I hope I helped some though, to at least get you started
Good luck
2007-05-29 09:09:47
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answer #6
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answered by Anonymous
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for the 2nd : If a line parallel to another line so it must be the slope of the 1st line = the slope of th 2nd line , and to get the slope of line its -(factor of X)/(factor of Y) for ur example the -(factor of X)= -4 and (factor of Y)= -2 How? cause the form of equation should be at that form 4X-2Y-8=0 so the factor of Y= -2 then the slope = (-4)/(-2) = 2 ,which is also the slope of requested line , and from the general form of any line: ( Y - Y1) = ( X - X1)*Slope note:(X1,Y1) = ( 1 , 5 ) .. i mean (X1,Y1) is any point lie on the requested line
so the requested line equation is: (Y-5) = (X-1)* (2)........... I hope that useful for u
2007-05-29 09:26:47
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answer #7
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answered by jan_kord2008 1
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to find the x-intercept you make y=0. To find the y-intercepty you make x=0.
2007-05-29 09:50:22
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answer #8
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answered by ღßutterflyღ 3
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Y intercept
2x - 3y = 9
2x - 3y - 2x = - 2x + 9
- 3y = - 2x + 9
- 3y / - 3 = - 2x / - 3 + (9 / - 3)
y = 2/3x - 3
- - - - - - - - - -
x intercept
2x - 3y = 9
2x - 3y + 3y = 3y + 9
2x = 3y + 9
2x / 2 = 3y / 2 + 9/2
x = 3/2y + 9/2
- - - - - - - - - -s-
2007-05-29 09:27:24
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answer #9
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answered by SAMUEL D 7
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y = mx + c
2x-3y = 9
3y = 2x-9
y = (2x-9)/3
y = (2/3)x-3
m = slope
m = 2/3
c = y intercept
c = -3
second one forgotten.,need time.., long years back i have done
2007-05-29 09:06:44
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answer #10
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answered by ss 4
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