Algebra 1
posted by Maria .
My little sister needs help on her homework and I don't remember really how to do this. I can't tell her if the answers or if she is doing them is the correct way. So if you could please tell me the answer and how you got it that would be great!

1.A ticket service is selling tickets to a concert. An order of 4 tickets has a price of $63 and an order of 6 tickets has a price of $91. Write an equation to find the price of any amount of tickets.
A.y = 9x
B.y = 32x
C.y = 14x + 7
2.A rental car company charges $75 for a 3day rental and $155 for a 7day rental. Write an equation to find the amount that the rental car company will charge for any number of days.
A.y = 20x + 15
B.y = 15x  20
C.y = 25x
3.Write the pointslope form of an equation of the line that passes through (2, 3) and has a slope of m = 3.
A.(y  2) = 3(x + 3)
B.(y  3) = 3(x + 2)
C.(y + 3) = 2(x + 2)
4.Write the slopeintercept form of an equation of the line that passes through
(3, 5) and has a slope of 6
A. y = 2x  6
B.y = 6x  13
C.(y  5) = 6(x  3)
5. State the domain of the function y=3/x
A. D: x ≠ 0
B.D: x <0
C.D: all real numbers

1.
Since adding 2 tickets increases the cost by $28, tickets must cost $14 each. The only logical choice is thus (C).
Check: 14*4+7 = 56+7=63 and 14*6+7=84+7=91
2.
This is exactly the same problem, just different numbers. Increasing the days by 4 raises the cost by $80,meaning $20/day. Choice (A)
3.
The slope between two points is m=∆y/∆x where ∆ means "change in"
So, the slope between (x,y) and any point on the line is the same value: 3.
In particular, the slop between (x,y) and (2,3) is 3. Symbolically, that is
(y3)/(x+2) = 3
or, (y3) = 3(x+2)
Choice (C)
4.
This one starts the same way, getting you to:
(y5)=6(x3)
However, they asked for the slopeintercept form, y=mx+b. So, solve for y:
y5=6x18
y=6x13
Choice (B)
5.
Division by 0 is not defined, so 3/x is not defined when x=0.
So, choice (A)