Parallel Lines

Parallel Lines

How do we determine parallel lines?

• we look at the slope!

• parallel lines have the SAME slope

• key: must be solved for slope intercept form y=mx+b

What do we do if they aren't in slope intercept form?

• we solve it!

• standard form to slope intercept -2x + 3y = 12

• point slope to slope intercept y-3=4(x-2)

  
  

Determine whether the lines are Parallel or Perpendicular or Neither

Multiple Choice

 $y=7x+2\ \ and\ y=7x-1$  

• perpendicular

• parallel

• neither

Multiple Choice

 $y=\frac{4}{5}x+2\ \ and\ y=\frac{-5}{4}x-1$  

• perpendicular

• parallel

• neither

Multiple Choice

 $y=\frac{-1}{3}x+2\ \ and\ y=\frac{1}{3}x-1$  

• perpendicular

• parallel

• neither

Multiple Choice

 $5x-y=4\ \ and\ y=\frac{-1}{5}x+7$  

• perpendicular

• parallel

• neither

Multiple Choice

 $3x-y=2\ \ and\ \ 12x-4y=4$  

• perpendicular

• parallel

• neither

When we have equations like...

• y=2

• x=-5

Multiple Choice

 $x=2\ \ and\ \ y=3$  

• perpendicular

• parallel

• neither

What if we have been given an equation and a point, and told to solve for a parallel or perpendicular line through that new point?

• pull out the slope from the given equation

• take the slope and the point and plug into point slope form and solve!

Multiple Choice

Given y=3x+8 write a new line that is parallel through the point (-4,6)

• y=3x+18

• y=-3x+18

• y=-1/3x+18