Help with Slope-Intercept Form

I'm having trouble understanding what to do with these problems..it would be great if you can help me!

Write an equation in slope-intercept form for the line that satisfies each set of conditions:
1) x-intercept 1/3, y-intercept -1/4


2) Passes through (2,-5), perpendicular to the line whose equation is y=1/4x+7



3) Passes through (-3,-1) parallel to the line that passes through (3,3) and (0,6)

Thanks

1) x intercept = 1/3
y intercept -1/4

for slope intercept form you need slope and y intercept

we have y intercept given but no slope

we need to find slope

if we know the x intercept is 1/3 that is another set of points we know
(1/3, 0 ) is the x intercept
(0, -1/4) is the y intercept

we can find slope from two points

m = (y2 - y1)/(x2 - x1)
m = (-1/4 - 0)/(0 - 1/3)
m = -1/4/(-1/3)
invert and multiply

m = -1/4 * (-3/1)
m = 3/4

now we know all we need
y = mx + b
where m = slope b = y intercept

y = (3/4)x - 1/4

thats the equation

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2) Passes through (2,-5), perpendicular to the line whose equation is y=1/4x+7

if an equation is perpendicular to another then the slope is negative reciprical

m1 = 1/4

m2 = -1/(1/4)
m2 = -4
the slope of the line we want is -4

a point on the line is ( 2,-5)

the equation we have so far is
y = -4x + b
put in the point we have and solve for b

b = y + 4x
b = -5 + 4*2
b = -5 + 8
b = 3

y = -4x + 3
thats the equation

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Passes through (-3,-1) parallel to the line that passes through (3,3) and (0,6)

ok we have to find the line that passes through (3,3) and ( 0, 6)

or at least the slope of the line we dont need more

m = (6 - 3)/(0 - 3)
m = 3/(-3)
m = -1


since the line we want is parallel to that it must have the same slope..

y = -1x + b

b = y + 1x
the point it passes through is ( -3, -1)
b = -1 + 1*(-3)
b = -1 - 3
b = -4

y = -x - 4
that is the equation for the line we want ..hope that helps show how to find the point..