Bài `3`

\(a,27\cdot35+27\cdot65-170\\ =27\cdot\left(35+65\right)-170\\ =27\cdot100-170\\ =2700-170\\ =2530\\ b,142-\left[50-\left(2^3\cdot10-2^3\cdot5\right)\right]\\ =142-\left[50-\left(8\cdot10-8\cdot5\right)\right]\\ =142-\left[50-\left(80-40\right)\right]\\ =142-\left(50-40\right)\\ =142-10\\ =132\)