64 + 34 : ( x * 3 - 15 ) = 70
65+34:(х*3-15)=70 34:(х*3-15)=70-65 34:(х*3-15)=5 5*(х*3-15)=34 15х-75=34 15х=34+75 15х=109 х=109:15 х=7,3 65+34:(7,3*3-15)=70 65+34:(21,9-15)=70 65+34:6,9=70 65+4,93=70 69,93=70 70=70