Answer:
6
Step-by-step explanation:
I'm so sorry if it's incorrect
Answer:
b. $31.44
Step-by-step explanation:
The tank holds 11.75 gallons. Tim will need to get half of this amount to bring the tank back up to half full; this is
11.75/2 = 5.875
The gas costs $4.50 per gallon; this means the cost is
5.875(4.50) = 26.4375 ≈ 26.44.
There is also a $5 refueling charge; this makes the total cost
26.44+5 = 31.44
18. s = 5r^2 + 7......making r the subject
s - 7 = 5r^2
(s - 7) / 5 = r^2...by taking the sqrt of both sides, it eliminates the ^2
( sqrt (s-7)/5) = r
19. h = ut - 1/2gt^2....u = 100, t = 1 4/5(or 9/5)...g = 6.4
h = (100)(9/5) - 1/2(6.4)(9/5^2)
h = 180 - 1/2(6.4)(3.24)
h = 180 - 3.2(3.24)
h = 180 - 10.368
h = 169.632 or 169 79/125
20. sorry..do not know this one
we can factor the whole thing:
(2sin(x) -1)(sin(x)+1) = 0.
Therefore, sin(x) = -1 and sin(x) = 1/2.
For the first one x = 3π/2 and the second is π/6 and 5π/6
So 3π/2, π/6 and 5π/6 are the solutions.
I do kind of have a problem with this because it doesn't mention if you should go over 360°. Otherwise, you have to add in an 2nπ into the equations like 3π/2 + 2nπ; 
but I don't know if that is necessary for you.
