1. 7(2t+5) -23t-11=14t+35-23t-11=-9t+24
2. 5(6,1-4,2a)+6,3a-4,7 =30,5-21a+6,3a-4,7= 25,8 -14,7a
3. 20+ 5(0,2y -4)=20+y-20=y
4. 2,1b-3,4a-(b-2,6a)=2,1b-3,4a-b+2,6a= -0,8a +1,1b
5. x- (4x-11)+(9-2x)= x-4x+11+9-2x=-5x+20
6. 4,6a-4b-(3,8b+3,5a)= 4,6a-4b-3,8b-3,5a=1,1a-7,8b
7. 2a-(8-a)+(3a-2)=2a-8+a+3a-2=6a-10