Let
x-------> the length side of the original cube
we have

Divide by
both sides

The system of equations is equal to
--------> equation 
--------> equation 
using a graphing tool
see the attached figure
we know that
the solution of the system of equations is the intersection both graphs
therefore
the solution is

therefore
<u>the answer is</u>

Answer:
.35 x + .70 (20) = .45(x+20)
50=x
Step-by-step explanation:
Let x = liters of 35% salt solution
We have 20 liters of 70%
We have a total of 20+x liters of 45%
.35 x + .70 (20) = .45(x+20)
Distribute
.35x + 14 = .45x +9
Subtract .35x from each side
14 = .10x +9
Subtract 9 from each side
5 = .10x
Divide each side by .1
5/.1 = x
50=x
You Need To Create An Equation Then Solve For Their Rates Of Travel.
Explanation:
The equation for this problem can be modeled in y = mx + b form.
m represents the rate of change and b represents the initial value or constant.
y = 10x + 20
x represents the number of hours he spent delivering newspapers
y is his total money after whatever number of hours he worked
The rate is 10, because it determines how much money he earns for each hour.
The y-intercept is 20, representing the starting amount of money in his bank account.
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form y=Kx
where
K is the constant of proportionality or slope of the linear equation
In this problem
x ----> is the number of months
y -----> is the total amount savings
we have the ordered pairs
(4,80) and (7,140)
so
Find the value of K
K=y/x
For (4,80)
K=80/4=20
For (7,140)
K=140/7=20
The value of K is the same for both ordered paits
that means------> is a proportional relationship
therefore
the linear equation is
y=20x
the answer is the option A, C and D