Subtract 3y and move it to the right
X= 1 - 3Y
Perimeter Formula:

Area Formula:

Set perimeter Formula equal to b:

Plug formula for be we just made above into the area Formula:

Solve for L (you'll have to use quadratic formula) then plug that back into the area Equation and solve for b.
Here's a link to where the problem has been explained before (they go into more detail than me).
https://brainly.ph/question/468631
lmk if you need any more help
Fibonacci is famous for his contributions to number theory.
In his book, Liber abaci he introduce the Hindu-Arabic place-valued decimal systems and the use of Arabic Numerals into Europe.He introduced the bar we use in fractions, previous to this, the numerator has quotations around it. The square root notation is also is Fibonacci method.
When taking square roots, you can't take square roots of negative roots of negative numbers. So, what will work for the domain of u(x) is what makes u(x) zero or more. We can make an inequality for that.
u(x) ≥ 0.

9x + 27 ≥ 0 by squaring both sides
9x ≥ -27
x ≥ -3
So the domain of the function is when x ≥ -3 is true.