# equations of lines

• Feb 21st 2007, 07:27 AM
Haxcake
equations of lines
Write the slope of a line that is parellel to each line
y=2x - 5
3x+y = 10

Write an Equation for the line containing the point (6,-2)
Parrell to the line 2x + y = 5
• Feb 21st 2007, 07:59 AM
CaptainBlack
Quote:

Originally Posted by Haxcake
Write the slope of a line that is parellel to each line
y=2x - 5
3x+y = 10

Write an Equation for the line containing the point (6,-2)
Parrell to the line 2x + y = 5

If you rearrange a linear equation into standard form:

y=mx+c,

then m is the slope, and all lines parallelto your line have this same slope.

You first line is already in standarf form, so the slope of lines parallel to it
is 2.

The secod equation: 3x+y=10 can be rewritten:

y=-3x +10,

so the required slope is -3.

The third equation can be rewritten: y=-2x+5, so the slope of the required
line is -2, so the line is of the form:

y=-2x+c

If this goes through (6, -2), we have:

-2 = -2*6 + c,

so:

c=-2 + 2*6 = 10,

and then the equation of the required line is:

y = -2x+10

RonL