A square has four even sides and the perimeter is equal to the sum of all of the sides.

So we can evaluate the equation for P and then solve for s.
Answer:
short form:0.23 Long Form:0.23076923076
Step-by-step explanation:
We have an exponential with a fractional base and a positive exponent, and a positive sign at front. Each time we multiply a fraction between zero and one by itself it gets smaller. So as x increases we'll go to zero. As x decreases it goes to positive infinity, as negative powers are the reciprocals of positive power.
The left end approaches positive infinity and the right end approaches zero.
For this problem you have yo set up two equations.
White shirts = w Yellow shirts = y
1st: w + y = 21
2nd: 9.95w + 11.50y = 235.30
Now we're going to do system of equations using substitution.
If w + y = 21, then y = 21 - w
If y = 21 - w, then you can substitute this in the second equation for y.
9.95w + 11.50(21 - w) = 235.30
9.95w + 241.5 - 11.50w = 235.30
-1.55w + 241.5 = 235.30
-1.55w = -6.2
w = 4, so 4 whites shirt were sold.
Now I'm finding out how many yellow shirts were sold using one of the two equations at the top.
w + y = 21
4 + y = 21
y = 17
So 17 yellow shirts were sold and 4 white shirts were sold.