Question

I need help understanding how to determine whether the graphs of equations are parallel,perpendicular,or neither.

Answer 1

\[y=x+11 and y=-x+2\] These are teh two equations but I dont understand how to find the slope to determine which they are.

Answer 2

See
http://www.khanacademy.org/math/algebra/linear-equations-and-inequalitie/equation-of-a-line/v/equations-of-parallel-and-perpendicular-lines

Answer 3

Thank you!!!

Answer 4

In case you did not figure it out, when you see an equation like
y= x+11
that is the equation of a line in slope-intercept form
y= mx+b

the m is the slope. The m is the number that multiplies the x
in your case, m is 1
y= 1x +11 (people don't bother to write the 1 because 1*x= x)

for the other equation
y= -x+2
this is also in y= mx+b form. m for this equation is -1. The slope is -1

perpendicular lines have "minus flipped" slopes. Example: if the slope of one line is \( -\frac{1}{2} \), a line perpendicular to it will have slope +2 (flip the -1/2 to get -2, then minus it - -2= +2)

For your problem, slopes 1 and -1 pass perpendicular the test: 1/1 (flip 1) then minus: -1/1 which is just -1.