Posted by **JOJO** on Wednesday, June 5, 2013 at 11:01pm.

(a)Given the points P(3,5),Q(8,10)and R(8,0),find the equation of a line which is perpendicular to QR and passes through the mid point of QR.

(b)The line 2x+3y=2 and 7x-3y=10 intersect at A . Find the equation of the line which passes through A and is perpendicular to the line 3x-4y=7

- math -
**Reiny**, Thursday, June 6, 2013 at 7:48am
a) let M(8,5) be the midpoint of QR.

QR is a vertical line, so its slope is undefined.

A line perpendicular to QR must be a horizontal line

A horizontal line through M(8,5) is imply

y = 5

(Where does point P enter the picture ? )

b) Add the two equations ...

9x = 12

x = 12/9 = 4/3

sub into the first ...

8/3 + 3y = 2

3y = -2/3

y = -2/9

point A is (4/3 , -2/9)

The new line is to be perpendicular to

3x - 4y = 7

So it must have the form 4x + 3y = C

but (4/3 , -2/9) lies on it, so

16/3 - 6/9 = c

times 9 ....

48 - 6 = 9c

c = 14/3

we have 4x + 3y = 14/3

or

12x + 9y = 14

## Answer This Question

## Related Questions

- math - i have more than one question so if u no any of the answers please tell ...
- precalc - I;m not sure if i am doing this right...I keep getting a negative ...
- Math 101 - Find the equation for each of the following items below: a. A line ...
- math - I need help with "write in equation in slope-intercept form for the line ...
- Math please. - What is the y-intercept of y = 2/3x + 2? I have to write it out ...
- Analytic Geometry - A line Q has an equation of x+5x+5=0. Find the equation of ...
- MAT221 - consider the line 8x-5y=-4 find the equation of the line that is ...
- Math - What is the y-intercept of y = 2/3x + 2? I have to write it out but how? ...
- Analytic Geometry - A line Q has an equation of x+5y+5=0. Find the equation of ...
- Math - Write a linear equation in slope intercept form for each of the following...

More Related Questions