(1) substitute T = 0C, v= 100, T = 10C, V = 103.5L into v = pt+q.100 = op+q1,/kloc.
3. let a be x, b be y. 0.5x+0.7=35 ①, x+0.4 = 40②.① times 2-②, and y=30. Substitute y=30 into ①, 0.5x= 14, x= 18.
4. There are 200 football players and 0/50 basketball players/kloc.
5. let the total income be x and the expenditure be y yuan. ( 1+20%)X-( 1- 10%)= 12000+ 1 1400①,x-y= 12000 ②。 ① Multiply by 10-② Multiply by 9 to get x=42000 and y=30000.