Answer:
Step-by-step explanation:
You are given that ...
 40x +40y = 3040
 80x +40y = 3760
Eliminate y by subtracting the first equation from the second:
 (80x +40y) -(40x +40y) = (3760) -(3040)
 40x = 720
 x = 18
Using the first equation to find y, we have ...
 40y = 3040 -40x
 y = 76 -x . . . . . divide by 40
 y = 76 -18 = 58
The cost of a bracelet is $18; the cost of a necklace is $58.