Ответ:
1. 3(х+6)–х–2(х+9)=3x+18-x-2x-18=0
2. 6–3(х+1)–(7–х)=6-3x-3-7+x=-1-2x
3. (8х+3)–(10х-6)–9=8x+3-10x+6-9=-2x
4. 5–2(х-1)–(-4–х)=5-2x+2+4+x=11-x
5. (7х+1)–(9х+3)+5=7x+1-9x-3+5=-2x+3
6. (3,4+2у)-7(у–2,3)=3.4+2y-7y+16.1=19.5-5y
7. 4(5х+2)-10(3х-3)+15=20x+8-30x+30+15=-10x+53
8. 4(х-1)-2(2х-8)+12=4x-4-4x+16+12=24
9. 5,6–3(2–0,4х)-0,4(4х-1)=5.6-6+1.2x-1.6x+0.4=-0.4x
10. 5(х-12)+6(х-10)–(х-1)=5x-60+6x-60-x+1=10x-119