Answer:
A book is worth $1 and a DVD is worth $12.
Step-by-step explanation:
The equations (2 unknowns and two equations, d is for a DVD and b is for a book):
For David: 3d+4b=40
For Anna: d+6b=18
Now multiply the second equation with -3 and add to the first equation:
3d+4b=40
−3d−18b=−54
Combined equation: −14b=−14 and b=1 (means that each book is worth $1).
Now for DVD price, use the second equation:
d=18−6 or d=12 (means that each DVD is worth $12).
A book is worth $1 and a DVD is worth $12.
Answer:
i think C
Step-by-step explanation:
tell me if i am wrong and hope you have a good day
Answer:
c. 5
Step-by-step explanation:
678 rounds to 700 and 218 rounds to 200. 700-200=500
Answer:

Step-by-step explanation:
y = x .....(1)
.... (2)
By solving equation (1) and equation (2)


or 
x = 0, x = 1
y = 0, y = 1
A = 
A = 
A = ![\frac{2}{3}[x^\frac{3}{2}]_{0}^{1}-\frac{1}{2}[x^2]_{0}^{1}](https://tex.z-dn.net/?f=%5Cfrac%7B2%7D%7B3%7D%5Bx%5E%5Cfrac%7B3%7D%7B2%7D%5D_%7B0%7D%5E%7B1%7D-%5Cfrac%7B1%7D%7B2%7D%5Bx%5E2%5D_%7B0%7D%5E%7B1%7D)
A = 
A = 