Answer:
C
Step-by-step explanation:
7x + 3y = 30 (equation 1)
-2x + 3y = 3 (equation 2)
9x = 27 (subtract the two equations to eliminate y)
x = 3 (divide by 9)
7 * 3 + 3y = 30 (Substitute x = 3 into equation 1, it doesn't matter which equation you substitute into)
21 + 3y = 30 (7 * 3 = 21)
3y = 9 (Subtract 21)
y = 3 (divide by 3)
Answer is (3, 3)
Answer:
a) 
b) The pollution level at 4 o'clock in the afternoon is of 280 parts per million.
Step-by-step explanation:
The pollution level in the center of a city at 6 am is 30 parts per million and it grows in linear fashion by 25 parts per million every hour.
This means that the pollution in t hours after 6 am is given by:
, which is the answer to question a.
b. The pollution level at 4 o'clock in the afternoon
4 in the afternoon is 10 hours after 6 am, so this is y(10).

The pollution level at 4 o'clock in the afternoon is of 280 parts per million.
Answer:
dude. why are you asking me?
Step-by-step explanation:
yuh.
Answer is B
9/4 <x <= 4
...........
Answer:
$38.84
Step-by-step explanation:
1) 48.00 x 0.07 = 3.36 (she must pay this amount)
2) 48.00 x 0.1 = 4.8 (she must tip this much)
48.00 - 4.8 + 3.36 = 39.84
She has 39.84 dollars she can use to order food with.