Algebra Homework Help! Anybody :)

We have a huge assignment and there's a couple I'm just STUCK on

Find the x- and y- intercepts for each equation:
15. y = 1/2x + 3
16. -2y = 5x - 12

Write the equation in point-slope form for the line through the given point with the given slope

27. (4,6);m = -5
28. (3,-1);m = 1
29. (8,5);m = 1/2
30. (0,-6);m = 4/3

A line passes through the given points. Write an equation for the line in slope-intercept form.

47. (2,5) and (4,8)
48. (1,6) and (7,3)

Find the x- and y- intercepts for each equation:
To find the x-intercept, set y = 0 and solve for x.
To find the y-intercept, set x = 0 and solve for y.
15. y = 1/2x + 3
0=1/2x+3
-3=1/2x
6=x
y=1/2(0)+3
y=3
16. -2y = 5x - 12
-2(0)=5x-12
0=5x-12
12=5x
12/5=x
-2y=5(0)-12
-2y=-12
y=6

Write the equation in point-slope form for the line through the given point with the given slope.
Just plug the given values into the point-slope formula, y-y1=m(x-x1)
27. (4,6);m = -5
y-6=-5(x-4)
28. (3,-1);m = 1
y+1=1(x-3)
29. (8,5);m = 1/2
y-5=1/2(x-8)
30. (0,-6);m = 4/3
y+6=4/3(x-0)

A line passes through the given points. Write an equation for the line in slope-intercept form.
y = mx + b: m=slope, b=y-intercept
To find the slope you can use m=(y1-y2)/(x1-x2)
Then use either point as the (x1, y1), along with then calculated slope, and plug in to the point-slope form. y-y1=m(x-x1)
47. (2,5) and (4,8)
m=(5-8)/(2-4)
m=-3/-2
m=3/2
y-5=3/2(x-2)
y-5=3/2x-3
y=3/2x=2
48. (1,6) and (7,3)
m=(6-3)/(1-7)
m=3/-6
m=1/-2
y-6=1/-2(x-1)
y-6=1/-2x+1/2
y=1/-2x-11/2

Find the x- and y- intercepts for each equation:
15. y = 1/2x + 3

The x-intercept is when y = 0.
The y-intercept is when x = 0

In your case
x = 0, y = 3 <<< that's point (0, 3)
y = 0, x = -6 <<< that's point (-6, 0)

Not hard, is it?
Do the other yourself.


Write the equation in point-slope form for the line through the given point with the given slope
27. (4,6); m = -5

y - y1 = m(x - x1)
m is your slope
(x1, y1) is the given point

in your case
y - 6 = -5(x - 4) <<< your point-slope equation

Not hard, is it?

I suggest you see these two videos for point-slope and slope-intercept forms
http://youtu.be/m2hi3TB3m7U
http://youtu.be/Tt0BjZT_qNg

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