Can you please help me solve and if you show work I would really appreciate it

You got the equations correct, great job on that!
Let "s" be the variable that represents how many shirts were bought. Let "p" represent the total price/cost.
Equation for the store at Town Center mall:
p = 80 + 3.5s (80 is base cost, and cost increases 3.5 per shirt)
Equation for the store in Arlington:
p = 120 + 2.5s (120 is base cost, and cost increases 2.5 per shirt)
We want to find a point where the systems are equal; thus, we are solving for a system of linear equations, and we already have the equations we need.
p = 80 + 3.5s
p = 120 + 2.5s
We know that variable "p" is equal for both equations; thus, we can combine both equations into:
80 + 3.5s = 120 + 2.5s
Subtract both sides by 2.5s
80 + 3.5s - 2.5s = 120 + 2.5s - 2.5s
80 + s = 120
Subtract both sides by 80
s = 40
Thus, both equations are equal when 40 shirts are bought.
To find the cost, use any of the two equations (or both) to find the total cost, which should be equal.
p = 80 + 3.5(40) = 220
p = 120 + 2.5(40) = 220
Thus, the total price/cost at both stores is $220.
Let me know if you need any clarifications, thanks!