dernier exos de mon dm de maths Équations je bloque svp

a)

5x-3x =10+1
2x = 11
x =11/2

b)
17x-15 -45x = 10x+15
-28x -10x = 15+15
-38x = 30
x = 30 / -38
x = -15/ 19

c)

2x + 3x-5 /2  + 3x+4 /5 = 0
20x /10 + 30x-50/10 +6x+8/10 = 0
36x-42/10= 0
36x/10 = 42/10
x = 42/10*10/36
x = 42/36
x = 21/18
x = 7/6