The choir sold boxes of candy and Teddy bears to raise money. They sold 4 times as many boxes of candy as they did Teddy bears. Bear sold for $11 each and candy sold for $5. They collected $558. How much of each item did they sell?

Teddy bears = t = 18
# boxes of candy = c = 72

Four times the number of teddy bears is how much candy they sold:
4t = c
11t + 5c = 558

So we will substitute the value of c into the second expression and solve for a numerical value of t

11t + 5(4t) = 558
11t + 20t = 558
31t = 558
t = 18

c = 4t
c = 4(18)
c = 72

Check the math:
11(18) + 5(72)
= 198 + 360
= 558

Please let me know if you have any questions

Understanding what? lol

X> -2 is the simplified version.