54: (5 + m) + (3*3+4*4) : 5=9*3-12:2 - (5*9-7*5)

54: (5+m) + (3·3+4·4) : 5=9·3-12:2 - (5·9-7·5)

54: (5+m) + (9+16) : 5=27-6 - (45-35)

54: (5 + m) + 25:5=27-6-10

54: (5 + m) + 5=11

54: (5 + m) = 11-5

54: (5 + m) = 6

5+m=54:6

5+m=9

m=9-5

m=4

54: (5+4) + (3·3+4·4) : 5=9·3-12:2 - (5·9-7·5)

54:9 + (9+16) : 5=27-6 - (45-35)

6+25:5=21-10

6+5=11