№1
-3x-1 = -5x+3
-3x-1+5x-3 = 0
2x-4 = 0
x = 2
________________________
(-3*2)-1+(5*2)-3 = 0
-6-1+10-3 = 0
0=0
________________________
y = -7
x = 2
_____________________________________________________
№2
Ответ: В, т.к. 3/4 = 0.75
_____________________________________________________
№3
- x = 0; 2*0+0 = 0
- х = 1/2; 2*(1/2)²+1/2 = 2*1/4+1/2 = 1/2+1/2 = 1
- х = 2/3; 2*(2/3)²+2/3 = 2*4/9+2/3 = 6/9+2/3 = 2/3+2/3 = 4/3
Ответ: С