The answer is A. You can get that in by plugging in and checking or by substitution. In order to use substitution here, you would plug in 3x + 3 into y in the first equation. You would then distribute the 2 and solve for x, which would give you 0. Then you could plug that into either equation to find that y = 3.
Answer:
1/4
Step-by-step explanation:

From the given function modeling the height of the ball:
f(x)=-0.2x^2+1.4x+7
A] The maximum height of the ball will be given by:
At max height f'(x)=0
from f(x),
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
thus the maximum height would be:
f(3.5)=-0.2(3.5)^2+1.4(3.5)+7
f(3.5)=9.45 ft
b]
How far from where the ball was thrown did this occur:
from (a), we see that at maximum height f'(x)=0
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
This implies that it occurred 3.5 ft from where the ball was thrown.
c] How far does the ball travel horizontally?
f(x)=-0.2x^2+1.4x+7
evaluationg the expression when f(x)=0 we get:
0=-0.2x^2+1.4x+7
Using quadratic equation formula:
x=-3.37386 or x=10.3739
We leave out the negative and take the positive answer. Hence the answer 10.3739 ft horizontally.
Answer:
1. a. 117.
2. $2,051.48
3. 592.82
4. 1472.01
5. d. 4116.11
6. d. 24
Step-by-step explanation:
Economic Order Quantity : 
Economic order quantity is 
EOQ = 117
2. ordering cost :
( total demand / EOQ ) * Ordering cost
( 600 / 117 ) * 400 = $2051.28
3. Holding cost :
Total demand * holding cost per unit
= 592.82
Reorder Point = Daily Demand * lead time
Reorder point = 600 / 350 * 14 = 24