I'm in 8th grade and taking Algebra 1, though if you sat in my class you'd assume it were a kindergarten class the way the behavior is. Anyway, I'm stuck on a (many, actually) questions in this packet which will end up being 10% of my grade. The current question I can't figure out is: "A line passes through the point (-3,2) and has a slope of 1/3. Which of the following points also lies on this line?: A. (-2,5) B. (5,6) C. (-9,1) D. (6,5)" I'm not really sure what to do... I figured that maybe if I put it in (y-y1)=m(x-x1) that maybe I could figure something out from there... so I did: y-2=1/3(x+3). Then for some reason I decided that maybe from there I should put it in as y=mx+b. So then I ended up with: y=1/3x+2... Then I just tried graphing it but I can't seem to make any of the points given lay across the line.
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A line passes through __ which point also lays across this line?
- Thread starter Dannielle
- Start date
"Lie" not "lay." Bet you did not expect to get English lessons here.I'm in 8th grade and taking Algebra 1, though if you sat in my class you'd assume it were a kindergarten class the way the behavior is. Anyway, I'm stuck on a (many, actually) questions in this packet which will end up being 10% of my grade. The current question I can't figure out is: "A line passes through the point (-3,2) and has a slope of 1/3. Which of the following points also lies on this line?: A. (-2,5) B. (5,6) C. (-9,1) D. (6,5)" I'm not really sure what to do... I figured that maybe if I put it in (y-y1)=m(x-x1) that maybe I could figure something out from there... so I did: y-2=1/3(x+3). Then for some reason I decided that maybe from there I should put it in as y=mx+b. So then I ended up with: y=1/3x+2... Then I just tried graphing it but I can't seem to make any of the points given lay across the line.
OK Thank you letting us know where you are in school. It helps us write answers that are appropriate for your level of mathematical education.
You had the right idea, but made an error.
\(\displaystyle m = \dfrac{1}{3} = \dfrac{y - 2}{x - (-3)} = \dfrac{y - 2}{x + 3} \implies \frac{1}{3}(x + 3) = y - 2 \implies \frac{1}{3}x + 1 = y - 2 \implies y = 3 + \frac{1}{3}x.\)
CHECK YOUR WORK
The equation above clearly has a slope of 1/3. And \(\displaystyle 3 + \frac{1}{3}(-3) = 3 - 1 = 2.\)
So (-3, 2) is a point on the line that graphs the equation.
Now all you need to do is to determine which of the other x-y pairs provided satisfy the equation.
\(\displaystyle x = 2 \implies y = 3 + \frac{1}{3}x = 3 + \dfrac{2}{3} = \dfrac{9 + 2}{3} = \dfrac{11}{3} \ne - 5.\) (2, - 5) is not on the line.
Now you do the rest.
EDIT: I posted a further response to your other post.
Last edited:
Hello, Dannielle!
You're off to a good start, but you made an error.
The equation of the line is: .\(\displaystyle y \:=\:\frac{1}{3}x + {\color{red}3}\)
Try it again . . .
You're off to a good start, but you made an error.
A line passes through the point (-3,2) and a slope of 1/3.
Which of the following points also lies on this line?
. . A. (-2,5) . . B. (5,6) . . C. (-9,1) . . D. (6,5)
The equation of the line is: .\(\displaystyle y \:=\:\frac{1}{3}x + {\color{red}3}\)
Try it again . . .
Thanks for all of the help. I'm obviously just exhausted when I get to the point that I can try a math problem four times and still mindlessly write down that 2+1=2, instead of 3.Hello, Dannielle!
You're off to a good start, but you made an error.
The equation of the line is: .\(\displaystyle y \:=\:\frac{1}{3}x + {\color{red}3}\)
Try it again . . .
Thank you again for the help!