# Lines through/parallel to planes?

• Feb 9th 2011, 11:54 AM
Bracketology
Lines through/parallel to planes?
The question is:
If the positive z-axis points upward, an equation for a horizontal plane through the point (-3,-2,4) is:

An equation for the plane perpendicular to the x-axis and passing through the point (-3,-2,4) is:

An equation for the plane parallel to the xz-plane and passing through the point (-3,-2,4) is:

I have a test on this TUESDAY, and any help with these would be greatly appreciated.
• Feb 9th 2011, 12:29 PM
Plato
If $\displaystyle P:(a,b,c)$ is a point in $\displaystyle \math{R}^3$ then:
$\displaystyle x=a$ is a plane parallel to the $\displaystyle yz\text{-plane}$ which contains $\displaystyle P$.
$\displaystyle y=b$ is a plane parallel to the $\displaystyle xz\text{-plane}$ which contains $\displaystyle P$.
$\displaystyle z=c$ is a plane parallel to the $\displaystyle xy\text{-plane}$ which contains $\displaystyle P$.
• Feb 9th 2011, 12:31 PM
Bracketology
Thanks again! You're always quick and accurate with your responses.