Minta tolong ya kakak cari soal no.12 Pakai cara

a. (3x + 1) + (-2x + 3) + 2(4x - 5) = 3x - 2x + 1 + 3 + 8x - 10 = x + 4 + 8x - 10 = 9x -6

b. 2(3x + 1) - 3(-2x + 3) + 4(4x - 5) = 6x + 2 + 6x - 9 + 16x - 20 = 12x - 7 + 16x - 20 = 28x - 27

c. 2(3x + 1) - [3(3x + 1) - {(-2x + 3) - 2(4x - 5)}] - (4x - 5) = 6x + 2 - {9x + 3 - (-2x + 3 - 8x + 10)} - 4x + 5 = 2x + 7 - (9x + 3 + 2x - 3 + 8x - 10) = 2x + 7 - 19x + 10 = -17x + 17