# algebra

posted by .

I have a few questions that I don't understand hope someone can help.

1)write an equation of th line, in point slope form, that passes through the two given points. (-17,8),(3,-2)
I figured (y-8)=-2(x+17) not sure

2) the graph of g(x) is f(x) vertically compressed by a factor of 1/7 and reflected in the x-axis what is the function rule for g(x)given f(x)=2x.

3)determine whether y varies directly with x if so find the constant of variation k and write the equation.
x y
7 11
8 13
9 15
10 17
I know you start with y=kx but then I'm lost.

not looking for just answers but if someone can explain I'd appreciate it

• algebra -

on number 3 y=kx
so would i divide y by x and if so I get 1.57, 1.62, 1.66, and 1.7..Is this right?

• algebra -

#1. If not sure, plug in the points and see whether they satisfy your equation. you will see that they don't even come close
The (y-8) and (x+17) bits are ok, but how did you come up with a slope of -2? (-2-8)/(3+17) = -1/2

Looks like you used ∆x/∆y for the slope, rather than ∆y/∆x!

#2: you want g(x) which produces a height 1/7 of f(x). So,

g(x) = 1/7 f(x)

Now, you want to reflect g(x) around the x-axis, so

h(x) = -g(x)
h(x) = -1/7 f(x) = -1/7 (2x) = -2/7 x

check: f(1) = 2
h(1) = -2/7 shrunk, reflected

that is correct. Since the ratio changes, it is not a constant k.

y does not vary directly with x

In fact, y increases by 2 for every increase in x by 1. So,

y = 2x-3

That pesky -3 fouls up the direct variation.

## Similar Questions

1. ### algebra

Write an equation in slope-intercept form of the line that passes through the given points: (-1/2,-1), (3,5/2). Also, write an equation in point-slope form of the line that passes through the given points: (6,-3), (-1,9). <soo sick …
2. ### algebra

write an equation in slope-intercept form of the line that passes through the given points. a. (-6,1), (3,-7) b. (-2/3,4), (6, -1/3) write an equation in point-slope form of the line that passes through the given poitns. c. (-2,5), …
3. ### algebra (check plz)

write an equation in slope-intercept form of the line that passes through the given points. a. (-6,1), (3,-7) b. (-2/3,4), (6, -1/3) write an equation in point-slope form of the line that passes through the given poitns. c. (-2,5), …
4. ### math

I have a few question so I will number them off. Please answer them for me I have a test tommorow and I am sure this can help other people too. 1.How do you make an equation that passes through a y-intercept and a certain point in …
5. ### math

i have more than one question so if u no any of the answers please tell me 1.) write the point-slope form of the equation of the line with slope -2 passing through the point ( -5, -9). 2.) write the point-slope form of an equation …
6. ### geometry

I would love for someone to check my work on the seven problems that I did. I would be eternally grateful. I am going to list my problems and answers. Even if you only want to check one of them, that would be great. 1. Write an equation …
7. ### Algebra

1.Tell whether the sequence is arithmetic. If it is, what is the common difference?
8. ### Algebra

Can you check my answer? 1. For the data in the table, dose y vary directly with X?
9. ### Mathematics

Can someone check my answers? 1. For the data in the table, does y vary directly with X?