a) \(120-5\cdot\left(20-2\cdot3^2\right)\\ =120-5\left(20-2\cdot9\right)\\ =120-5\left(20-18\right)\\ =120-5\cdot2\\ =120-10\\ =110\)
b) \(2^5:2^3-3\cdot3^2+5\cdot7\\ =2^2-3^3+35\\ =4-9+35\\ =\left(-5\right)+35\\ =30\)
c) \(35\cdot\left(85-47\right)+85\cdot\left(47-35\right)\\ =35\cdot85-35\cdot47+85\cdot47-85\cdot35\\ =\left(35\cdot85+85\cdot47\right)-\left(35\cdot47+85\cdot35\right)\\ =85\left(35+47\right)-35\left(47+85\right)\\ =85\cdot82-35\cdot132\\ =6970-4620\\ =2350\)
b) 25 : 23 - 3 . 32 + 5 . 7
= 22 - 33 + 35
= 4 - 27 + 35
= -23 + 35
= 12
c) 35. ( 85 - 47 ) + 85. ( 47 - 35 )
= 35 . 85 - 35 . 47 + 85 . 47 - 85 . 35
= ( 35 . 85 - 85 . 35 ) - 47 . ( 35 - 85 )
= 0 - 47 . (-50)
= -2350
