Help On Algebra Questions?

Question

In slope-intercept form :
1. Perpendicular to y= 3/4x - 2 and passes through (-12,7).
2. Perpendicular to the y-axis and passes through (-2,5).
3. Find the coordinates of the midpoint of the line segment with endpoints (-3,6) and (-1,-9).
4. P is the midpoint of the line segment AB. The coordinates of P are (5,-6). The coordinates of A are (-1,10). Find the coordinates of B.
5. A carpenter is building a stairway. The depth of each tread is 10 inches. The height of each riser is 8 inches. What is the steepness (slope) of the stairway?
6. The endpoints of AB are A (-4,8) and B (12,-4). Find the coordinates of P if P lies on AB and is 3/8 the distance from A to B.
7. Find the equation in slope-intercept form of the line that is perpendicular to AB and passes through the midpoint of AB. Let
A = (-6,2) and B = (4,-10).

Answer 1

1. Perpendicular to y= 3/4x - 2 and passes through (-12,7).

slope = -4/3
y-7 =(-4/3) (x + 12 )

2. Perpendicular to the y-axis and passes through (-2,5).
y=5

3. Find the coordinates of the midpoint of the line segment with endpoints (-3,6) and (-1,-9).

midpoint= ( (-3-1)/2 , (6-9)/2 ) = (-2, -3/2)

7. Find the equation in slope-intercept form of the line that is perpendicular to AB and passes through the midpoint of AB. Let
A = (-6,2) and B = (4,-10).

slope of perpendicular line= (-10 -2 )/( 4-(-6)) = -12/10 = -6/5
midpoint of AB = ( (-6+4)/2, (2-10)/2 ) = (-1,-4)
so
eq. of desired line: y+4 = (5/6) (x +1) .

Answer 2

4. P is the midpoint of the line segment AB. The coordinates of P are (5,-6). The coordinates of A are (-1,10). Find the coordinates of B.

P = ( (-1+x)/2, (10+y)/2) = (5,-6)
so (-1+x)/2 = 5
and (10+y)/2 = -6

-1+x =10
x=11, and
10+y=-12
y=-22
so B=( 11, -22).

Answer 3

I'm not going to do all of them, since that's probabaly cheating.

1)Perpendicular to y= 3/4x - 2 and passes through (-12,7).

subsitute---> y=mx+b -----> 7=m(-12)+b

perpendicular lines have slopes that are the opposite of each other's reciprocals. so if the slope of one line is 2/5, the slope of a line perpendicular to it is -5/2 . to make sure you got it right, multiply the two together. if you get -1, you did it right

y=3/4x-2
slope of a perpendicular line----> -4/3

7=-4/3(-12)+b

now solve for b

7=16+b

b=-9

your final answer is y=-4/3x-9

Answer 4

Open your book and find the following information:

a. formula for lines perpendicular to a line
b. midpoint formula
c. definitions of endpoint, midpoint, slope
d. formula for slope of line in slope-intercept form
e. equations for lines you can use given two points, one point and slope

Write these pieces of info on separate note cards and keep in front of you while working on these problems.

I also suggest drawing out your problems, preferably on graph paper, as many students are visual learners.

Answer 5

My first answer was 17th Floor... However, what happens from this point; The elevator goes down again, and you get off. Acorrding to the pattern, on which floor are you now? The pattern starts all over again...??? 17-4+8-3+9= 27th Floor.

Answer 6

You must have a lot of hw before Christmas break :-)
First, refer to your notes and book. Try to follow each step from your notes to complete the problems. If you still don't understand some/most, just email me.

Answer 7

it's almost christmas. Just forget about school stuffs and have some fun.

Answer 8

It's Friday before Christmas, why are you doing math?

Answer 9

Oh boy... here goes nothing haha
1. y=-(4/3)x-9
2. x=5
3. (-2,-7.5)
4. (11,-22)
5. 8/10
6. (2,3.5)
7. y=(5/6)x-(29/6)
you're welcome

Answer 10

I'd help You but.. STOP CHEATING AND USE YOUR BRAIN!!!!!!! =0!