we can write an equation from each statement
Coach Tassone had to buy new equipment for the football team. He bought 15 new items
we add the number of each item and the total is 15
so

where j is the number of jerseys and h the number of helments
He bought jerseys, which were $38 cach, and helmets, which were $S6 each, and paid a total of $678.00
we multiply the number of each item by the price and add all to obtain the total cost

so, we have two equations and two unknowns

We use the elimination method
multiply the first equation by -38

now we add the equations

now we can solve for h

the number of helmets is 6, now we can repalce the value of h on any equation to find j
i will replace on the first equation

solve for j

the number of jerseys is 9