Setting: There are X students in the music class and Y students in the art class.
According to the meaning and known, there are:
x =(2/5)(y+58)…………………………( 1)
y =(3/7)(x+58)………………………………(2)
from( 1):5x-2y- 1 16 = 0..............(3)
From (2): 7y-3x-174 = 0 ............... (4)
(3)×3+(4)×5:( 15x-6y-348)+(35y- 15x-870)= 0
Finishing: 29y- 12 18=0
Solution: y=42 (person)
(3)×7+(4)×2:(35x- 14y-8 12)+( 14y-6x-348)= 0
Finishing: 29x- 1 160=0
Solution: x=40 (person)
A: There are 40 students in the music class and 42 students in the art class.