We simplify the equation :
2(x+3) + 5x = 34
= 2x + 6 + 5x
= 7x + 6
So, 7x + 6 = 34
x = (34-6)/7 = 4
Equation A : 6x - 22 = 2
x = (22+2)/6 = 4 (so it's equvalent).
Equation B : x/5 = 4
x = 4 x 5 = 20 (not equivalent)
Equation C :
3x - 6 = 12
x = (12+6)/3 = 6 (not equivalent)
Equation D : 6x = 18
x = 18/6 = 3 (not equivalent)
So, it's equation A