d)
1/3(x²+x)+2/3=2(2/3-2x)+11+1/3x²|·3
x²+x+2=6(2/3-2x)+33+x²
x²+x+2=4-12x+33+x²
x²-x²+x+12x=4-2+33
13x=35|:13
x=35/13
x=2 9/13
