Finding an Equation

R

ronnie

New member
Joined
Sep 2, 2005
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14
Ok, I need help on this one to. The problem is:

Find the equation of the line that passes through the point(4,2) and is perpendicular to the line 3y-2x=5.


I have already put 3y-2x=5 into standard form. I am stuck after that.

Thanks again for any help.
 
I don't know what you mean by "standard form" (texts vary in their definition of this term), and I'm not sure why you'd want to. Instead, solve for "y=", read the slope "m" off the equation, and then flip and change the sign to get the perpendicular slope.

Then use whatever method you have learned to plug the new slope and the given point into the new line equation.

Eliz.
 
Stapel:

Thank you for your help...

But I need to know what method to use. I meant that I had put it into the y form(on paper, not on the post).

I really appreciate it!!!
 
ronnie said:
I need to know what method to use.
Click to expand...
"Method" to do what? Please clarify how far you've gotten and where you are having difficulty. Thank you.

Eliz.
 
The standard straight line formula is y = mx + b m being the slope and b being the y intercept.

You are given 3y - 2x = 5 which is convertible to y = 2x/3 = 5/3

The line perpendicular to this line has the opposite slope.

Therefore, the line you seek is y = -2x/3 + b (b = the y interecept of the line)

Since the point (4,2) is on this line, 2 = -2(4)/3 + b making b = 14/3 and your perpendicular line y = -2x/3 + 14/3.
 
TchrWill said:
The standard straight line formula is y = mx + b...
Click to expand...
Actually, that's the "slope-intercept form" of the line. "Standard form" is either "Ax + By + C = 0" or "Ax + By = C", with A > 0, and A, B, and C usually required to be integers.

Eliz.
 
Why not keep it up. One more post won't matter.

Actually the perpendicular to
3y - 2x = 5
or
y = (2/3)x + 5/3
where m = 2/3) has a slope of
-(3/2)
the negative of the reciprical of the first slope.
m and -1/m are at right angles.
--------------------
Gene
 
No, I think it was just a mental glitch. We are all prone to them. That's why we keep an eye on each other. :evil:
-----------
Gene
 
My most humble apologies Ronnie. I accidentally left out one important word in my solution description.

The standard straight line formula is y = mx + b m being the slope and b being the y intercept.

You are given 3y - 2x = 5 which is convertible to y = 2x/3 = 5/3

The line perpendicular to this line has a slope equal to the negative reciprocal of the slope of the given line or - 3/2.

Therefore, the line you seek is y = -3x/2 + b (b = the y interecept of the line)

Since the point (4,2) is on this line, 2 = -3(4)/2 + b making b = 8 and your perpendicular line y = -3x/2 + 8.

Sorry for the misdirection. It happens.
I truly hope it did not cause you any cofusion.
 
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