Answer:
8 marbles
Step-by-step explanation:
Since Carl has 7 times as many marbles as Bill (who is the base unit), Carl's number of marbles is equal to 7 units.
7 units = 56
1 unit =

Bill has 8 marbles.
4x - 5y = -12
-x + 5y = 18
Add the equations together:
4x + -x = 3x
-5y + 5y = 0
-12 + 18 = 6
So now you have:
3x = 6
Divide both sides by 3:
X = 2
Now you have the value of x, replace x with 2 in one of the equations and solve for y:
4(2) -5y = -12
8 -5y = -12
Subtract 8 from both sides:
-5y = -20
Divide both sides by -5:
Y = 4
The solution is x = 2 and y = 4 which is written as (2,4)
Answer:
1. 2^x =64 is option number 4. 6
2. x= (2/5)^3 is option number 1. 8/125
3. 3•(3^4) = 3^x is option number 3. 5
4. 16/25 = x^2 is option number 2. 4/5