Can someone me on this?

the swimming team is ordering shirts. the cost (y) in dollars of (x) shirts is calculated by using the rule y=20x+40.
a) identify the slope and y-intercept
slope:
meaning:
b) how much will 15 sweatshirts cost?
c) if the bill was $1,000, how many shirts were ordered?

2) write a rule in slope-intercept form for the linear function that has (1,5) and (4, 11)

3 y=8x-25
y=6x-5
solve the system of equations above

5.)which region indicates the intersection of the system 3x+4y> 8 and -2x+4y> 12

6) write and solve a system of equations to the following.
two times antonio; s age plus sara's age equals 35. sarah's age is also 5 times antonio's age. how old is sarah?

1)
a. y=mx+b
m=slope
b=y-intercept

y=20x+40
The slope is 20.
The y-intercept is 40.

b. y =cost
x= # of shirts

y=20x+40
15 sweatshirts would make the equation y=20(15)+40
y=300+40
y=340
15 shirts would cost $340.

c. y=20x+40
$1000 would make the equation 1000=20x+40
1960=20x
98=x
Paying $1000 would get the swim team 98 shirts.

2)
(1,5) (4,11)
(x,y) (x1, y1)
y+y1=m(x+x1)
Pick a point and substitute it into the equation.

y+5=m(x+1)

To find the slope of a line, use the following equatIon:
y-y1/x-x1
11-5/4-1
6/3=2
The slope of the line is 2. Plug it into the equation for m.

y+5=2(x+1)
Solve the equation.
y+5=2x+2
y+3=2x
Put the equation in slope-intercept form.
y=2x-3

3)
y=x-25
y=6x-5

Plug one equation into the other.
x+25=6x-5
Solve.
x+30=6x
30=5x
6=x

Now plug 6 into one of the equations.
y=6x-5
y=6(6)-5
y=36-5
y=31

The answer should be in the form of a point.
(6,31)

5) I'm sorry, don't know how to solve this. You can Google how to graph two inequalities, though.

6)
Antonio's age can be represented by x.
Sarah's age can be represented by y.
2x+y=35
5x=y

Plug 5x into the first equation.
2x+5x=35
Solve.
7x=35
x=5

Antonio is 5 years old.
To find Sarah's age, plug Antonio's age into the equation for Sarah's age.

5x=y
5(5)=y
25=y

Sarah is 25 years old.