а) 2(4–9d)–(2d+3)=–8(4–d)+3(1+2d) б) 5(2–3b)–4(6+2b)=28–(b–2) в) –2(3x+4)+(6x+8)=4(5x–2–(5x+8) г) 8(4–3y)–(7–2y)=–(6+3y)+8(y–2)