află x :[(x×2) ÷6]÷15=13
b ba rog

[ ( x • 2 ) : 6 ] : 5 = 13
[ ( 2x ) : 6 ] : 5 = 13
[ ( 2x ) : 6 ] • 1/6 = 13
2x/6 • 1/5 = 13
x/3 • 1/5 = 13
x/15 = 13
x = 195