Graph Problem

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Graph Problem

by gmat009 » Wed Oct 01, 2008 5:37 pm
The graph of which of the following equations is a straight line that parallel to line I in the figure above? {Refer to attached figure}

(A) 3y - 2x = 0
(B) 3y + 2x = 0
(C) 3y + 2x = 6
(D) 2y - 3x = 6
(E) 2y + 3x = -6
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by EricLien9122 » Wed Oct 01, 2008 5:58 pm
IMO: A


OA?

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by gmat009 » Wed Oct 01, 2008 6:13 pm
OA is A. Can you plz. explain

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by mental » Thu Oct 02, 2008 4:34 am
Line in the figure
calculate the slope
we have two points, one on y axis (0,2) and another on x axis (-3, 0)

slope m = y2-y1/x2-x1 = 2-0/0-(-3) = 2/3

equation of line in figure = y=mx+c
c = y ordinate, when line passes on y axis = 2
y=2x/3 + 2 or 3y = 2x + 6

though we dont need to calculate the equation of line.....

now from the options:
keep y on one side and rest terms on other side

we see that only 1st three have 3y
rule out D and E
among b and c the x term is negetive

where as when the lines are parallel they have same slope
A give the same slope

once this is understood, you can see that all this explanation will not be required and the answer can be found by just looking at the options

..............................................................

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by gmat009 » Thu Oct 02, 2008 5:42 am
mental wrote:Line in the figure
calculate the slope
we have two points, one on y axis (0,2) and another on x axis (-3, 0)

slope m = y2-y1/x2-x1 = 2-0/0-(-3) = 2/3

equation of line in figure = y=mx+c
c = y ordinate, when line passes on y axis = 2
y=2x/3 + 2 or 3y = 2x + 6

though we dont need to calculate the equation of line.....

now from the options:
keep y on one side and rest terms on other side

we see that only 1st three have 3y
rule out D and E
among b and c the x term is negetive

where as when the lines are parallel they have same slope
A give the same slope

once this is understood, you can see that all this explanation will not be required and the answer can be found by just looking at the options

..............................................................
My question is how we calculated y intercept.
OA is A and according to that equation y intercept is 0.

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by reacher » Thu Oct 02, 2008 7:00 am
gmat009 wrote:
mental wrote:Line in the figure
calculate the slope
we have two points, one on y axis (0,2) and another on x axis (-3, 0)

slope m = y2-y1/x2-x1 = 2-0/0-(-3) = 2/3

equation of line in figure = y=mx+c
c = y ordinate, when line passes on y axis = 2
y=2x/3 + 2 or 3y = 2x + 6

though we dont need to calculate the equation of line.....

now from the options:
keep y on one side and rest terms on other side

we see that only 1st three have 3y
rule out D and E
among b and c the x term is negetive

where as when the lines are parallel they have same slope
A give the same slope

once this is understood, you can see that all this explanation will not be required and the answer can be found by just looking at the options

..............................................................
My question is how we calculated y intercept.
OA is A and according to that equation y intercept is 0.
You don't need to calculate the y intercept. Remember that we are looking for a parallel line and option A equation just translates into a line that is parallel to line 1 and crosses Y at 0. To understand it further, try to simplify option C. It translates into Y= 2/3X -2. Now look for -2 in the Y axis of the graph and you realize that the line is not parallel.