# Are these lines parallel?

• Apr 28th 2010, 11:02 AM
aquamistique
Are these lines parallel?
1.) y=1/6x+8
-2x+12y =-11

2.)y = 5x + 6
-18x + 3y = –54

Could someone show me how to do these problems? I keep asking people t oshow me how, but none of them do. They just tell me the answer, I want to know how to do the problems step by step, because I will be taking a test with similar problems soon.
• Apr 28th 2010, 11:19 AM
Amer
Quote:

Originally Posted by aquamistique
1.) y=1/6x+8
-2x+12y =-11

2.)y = 5x + 6
-18x + 3y = –54

Could someone show me how to do these problems? I keep asking people t oshow me how, but none of them do. They just tell me the answer, I want to know how to do the problems step by step, because I will be taking a test with similar problems soon.

when two lines parallel that means their slopes are equal

\$\displaystyle y = 1/6 x +8 \$
\$\displaystyle -2x+12y=-11 \$

\$\displaystyle dy/dx = 1/6 \$

\$\displaystyle 12y = 2x -11 \$
\$\displaystyle dy/dx = 2/12 = 1/6 \$

first two pairs are parallel to each other since their slopes same for all x values