Answer:
, 
Step-by-step explanation:
<h3>
I will use the elimination method.</h3>
We want to make the X's the same:


Because the signs of the X's are the same we subtract the 2 equations to make:
(I put the second one on top of the 1st)

So:

Substitute y into either equation 1 or 2:
(I chose equation 1)



So:

Answer: C & D
Step-by-step explanation:
Its $800 because to find interest u can use the formula I=PRT p is principal which is 500 times r which is rate-15/100(=15%) times 4
so the interest is 500×15/100×4=300
then u add 300 to 500 because the interest adds more money to the loan
1/4 (8 + 6z + 12)
------------------------------------------------------------
Combine like terms :
------------------------------------------------------------
1/4 (6z + 20)
------------------------------------------------------------
Apply distributive property :
------------------------------------------------------------
1/4(6z) + 1/4(20)
3/2z + 5
------------------------------------------------------------
Answer: 3/2z + 5
------------------------------------------------------------
x/110 = (320-x)/90
<span> Cross multiply</span>
90x = 35200-110x
200x=35200
X = 35200/200 = 176 (distance traveled by train going 110 mph
176/110 = 1.6 hours = 1 hour and 36 minutes
Check: 110*1.6 = 176, 90*1.6 = 144
176+144 = 320
it will take 1.6 hours ( 1 hour 36 minutes) for the trains to meet