Am I'm Right?

Question

I just finished doing my math hw and I'm hoping if there is someone out there to check my work.

Find the slope of a line perependicular to the graph of each equation.
1. y=x
my answer: y= -1/x

2. y=0.25x
my answer: y= -1/.25x

Write an equation that satisfies the given conditions through (1,6)
1. perpendicular to y= -4-5/2
my answer: 6= 1/4(1)-5/2

Thanks.

Answer 1

1. Since it asks for just the slope, the answer should be just -1, so your equation should be y=-x. (-1/x is not a linear function!)

2. You are correct, although you can simplify that to y=-4x.

3. The perpendicular line has an equation of y=(1/4)x+b. (You can't just plug in the same y-intercept, because it will not be the same.) So then solve for b using the points given.

6=(1/4)(1)+b
b=6-(1/4)=23/4

Therefore the line should be y=(1/4)x+(23/4)

Answer 2

Since the first two problems ask for slopes, you should have said something like "the slope = -1" and "the slope = -4".

The last problem needs a little work. You're right, that the slope of the perpendicular needs to be 1/4. So we have:

y = 1/4x + b
6 = 1/4(1) + b
6 = 1/4 + b
b = 5 3/4

So the last equation should be y = 1/4x + 5 3/4 (or 23/4)

Answer 3

I'm afraid you aren't right there.

The first question actually asks for the slope, not the line.
The slope of y=x is 1, so the slope of a perpendicular line is -1/1 = -1. (Note: an equation of a possible line would be y = -x + c, not -1/x).

The slope of y=0.25x is 0.25, so you get -1/0.25 = -4 slope.

I think your problem was that you were doing -1/(the whole thing, including x) rather than just -1/slope.

For the second one, I don't know what you mean, as you have no xs :)

Answer 4

The slope of y=x is 1 since it's really y=1x
so slope of perpendicular is negative reciprocal
or -1

2. slope is simpy -1/.25 or -4

last part
equation is y = -4x + c
plugging in
6=-4(1)+c
solving for c, c=10
so equation is y=-4x+10