Graphing Coordinates, slopes, line equations, etc.

[what1sth1s]

hi my teacher was nice enough to let me do all my corrections on my failed test so that she could give me 50%. unfortunately she says she cant help me with them but the thing is if i didn't do the question i obviously don't know how to do it at all. so here i am. we learn at a really fast pace so maybe thats why this stuff isn't getting into my brain. heck i already forgot the stuff we did in the first week.

anyways here are some questions im stuck on.

What is the slope of all lines parallel to 8x-2y=5?

Write the equation of the line that contains (-5,8)?

Change 3x+2y-8=0 to y-intercept form (y=mx+b)

Write the equation of the line that contains (-1,7) and is parallel to the line y=-2x-5

Thanks a lot.

 

[tkhunny]

Re: Graphing Coordinates

unfortunately she says she cant help me with them

I wish I knew what that means. Doesn't sound right to me.

What is the slope of all lines parallel to 8x-2y=5?

Slope-intercept form is always useful. Solve for 'y' and read the slope from the x-coefficient.

Write the equation of the line that contains (-5,8)?

A bit tricky, as it is not completely defined. ANY line through (-5,8)? I'll use the Point-Slope form. (y-8)=m*(x+5). Pick a value for 'm'.

Change 3x+2y-8=0 to y-intercept form (y=mx+b)

Isn't that the Slope-Intercept form? Anyway, just solve for 'y'. Can you do that? Please demonstrate.

Write the equation of the line that contains (-1,7) and is parallel to the line y=-2x-5

Same as the poorly defined one above. (y-7) = m(x+1), except we are given a slope, m = -2. Simple as that.

Reality Check - If you really are struggling with ALL these, you simply MUST go have a heart-to-heart chat with your teacher. You may be in the wrong class.

 

[tkhunny]

PKA Alert

"y-intercept form"

Am I out of date on this one? Is this new, less descriptive name beginning to invade textbooks?

 

[jonboy]

Re: PKA Alert

"y-intercept form"

Am I out of date on this one? Is this new, less descriptive name beginning to invade textbooks?

No it is not. Just probably an error on What1sth1s part.

 

[pka]

Re: PKA Alert

"y-intercept form"

Am I out of date on this one? Is this new, less descriptive name beginning to invade textbooks?

Not as far as I know! That form is the slope-intercept form.
The intersept form is:

\(\displaystyle \L
\frac{x}{a} + \frac{y}{b} = 1\quad \left[ {ab \not= 0} \right]\)

 

[tkhunny]

I feel better. Always good to have an authoritative review.