If abc company sells each of their t shirts for $8 with a $10 printing fee and bad company sells their t shirts for $5 with a $25 printing fee, at which point would the same amount of t-shirts cost the same amount of money

In this problem you have a system of equations. That means that you have two different equations; the first equation deals with the ABC company and is eight dollars times the number of shirts plus $10 equals the cost. The second equation is for the BAD company whose equation is five dollars times the number of shirts plus $12 equals the cost.
ABC company: 8s + 10 = c —> c = 8s + 10
BAD Company: 5s + 25 = c —> c = 5s + 25
Since these equations look like y = mx + b, let c, cost be y and s, total sale, be x
y = 8x + 10
y = 5x + 25

The original prompt is really asking you to solve the system of equations. If you can use a graphing calculator, it would be easy to type these two equations into the graphing Prompt. You could either look at the graph and determine where the lines cross or look at the table and determine the values which are the same. ... or solve it mathematically...
8x + 10 = 5x + 25
-5x. -5x
3x + 10 = 25
- 10 -10
3x =15
x = 3

y=5x + 25
y = 5(3) + 25
y = 15 + 25
y = 40
(3, 40) So for both equations three shirts would cost $40. Of course, you should check both equations and make sure that they have the same answer.