Question 897671
I will setup the majority of the solution process completely in symbols, and you can finish from where my response stops.


Say your variables are this way:
w = 22 feet pool width
L = 28 feet pool length
A = area of just the walkway around pool
x = unknown uniform width of the walkway around pool


The unknown variable to solve in this arrangement is x.


Pool area, wL.
Total area of pool and walkway, {{{(w+2x)(L+2x)}}}
WALKWAY AREA, {{{highlight_green((w+2x)(L+2x)-wL=A)}}}


Solve for x, the uniform width of walkway.
{{{wL+2Lx+2wx+4x^2-wL=A}}}
{{{4x^2+12Lx+2wx=A}}}
{{{4x^2+(2w+2L)x-A=0}}}
You could choose to substitute values now and perform some numeric simplification, often possible in academic problems; but you do not always know.


Staying in symbolism,
{{{x=(-2w-2L+- sqrt(4(w+L)^2-4*4*(-A)))/(2*4)}}}
{{{x=(-2w-2L+- sqrt(4(w+L)^2+16A))/(2*4)}}}
{{{x=(-2w-2L+- 2sqrt((w+L)^2+4A))/(2*4)}}}
{{{highlight(x=(-w-L+- sqrt((w+L)^2+4A))/4)}}}
One of these will make sense and one of them will not make sense.  Choose the one with sensible meaning.