Answer:

Step-by-step explanation:
Water is being pumped into an inflated rubber sphere at a constant rate of 0.03 cubic meters per second.
So, dV/dt = 0.03.
We want to show that dS/dt is directly proportional to 1/r.
In other words, we want to establish the relationship that dS/dt = k(1/r), where k is some constant.
First, the volume of a sphere V is given by:

Therefore:

Next, the surface area of a sphere S is given by:

Therefore:

We can divide both sides by 2:

We can substitute this into dV/dt. Rewriting:

So:

Since dV/dt = 0.03 or 3/100:

Therefore:

Where k = 3/50.
And we have shown that dS/dt is directly proportional to 1/r.
There are 3 ways of solving a simultaneous problem, substitution method, elimination method and Gauss-Jordan method. I'm gonna use the substitution method since it's easier and i think it would suit your level more.
First let's try solving for y since it's easier to start with.
Firstly we have to find an equation for x:

Great, now we can use the substitution method to find the value of y using the first equation:

Now we know that y=1 we can solve the first equation we made:

And the answer is 
Double check:

And that's our final answer! (4,1)
Answer:
x = 5/8
Step-by-step explanation:
Isolate the variable by subtracting 1/8 from both sides:
3/4 - 1/8 = 5/8
Now, the equation is:
x = 5/8
Therefore, the answer is 5/8
Answer:
Step-by-step explanation: