Pre Algebra
posted by Roosevelt on .
Given an equation of a line, how do I find equations for lines parallel to it going through specified points Simplifying the equations into slopeintercept form.
1. y= 2x 4; (1, 3) how do I write the equation of a line parallel to the given line but passing through the given point
2. y= 3x + 3; (1,1) how do I write the equation of a line perpendicular to the given line but passing through the given point

It must have the same slope: 2
Now you have a point and a slope, so the line is
y3 = 2(x1)
same idea, but you want the perpendicular slope, which is the negative reciprocal of the line's slope: 1/3
y1 = 1/3(x1)
review the various forms of the equation of a line:
standard
pointslope
twopoint
slopeintercept 
1. Y = 2x  4. (1,3).
Parallel lines have equal slopes:
m1 = m2 = 2.
Y = mx + b = 3
2*1 + b = 3
b = 3+2 = 5
Eq: Y = 2x + 5
2. Y = 3x+3. (1,1).
The slope of the line is equal to the negat1ive reciprocal of the slope of the given line.
m1 = 3
m2 = 1/3.
Y = mx + b = 1
(1/3)*1 + b = 1
b = 1 + 1/3 = 1 1/3 = 4/3
Eq: Y = (1/3)x + 4/3