Răspuns :

[5*(5x-5)-120]*5-25=125

[5*(5x-5)-120]*5=125+25

[5*(5x-5)-120]*5=150

5*(5x-5)-120=150:5

5*(5x-5)-120=30

5*(5x-5)=120+30

5*(5x-5)=150

5x-5=150:5

5x-5=30

5x=30+5

5x=35

x=35:5

x=7

Răspuns:

[5×(5×5)-120]×5-25=

(5×25-120)×5-25=

(125-120)×5-25=

5×5-25=

25-25=0