X2 20 2 9x. 2x+1/3-4x-x2/12 x2-4/9. X-2/5+2x-5/4+4x-1/20=4-x. (4x -3)/2 +(2x-1)(2x+1)=24. X3+5x=4x+20. X2-18x+81/81-x2. X2+18x+81. (X-9) : x2-18x+81. (X-9):x2-18x+81/x+9. X2-9x+20 0. (X2-5x+2)(x2-5x-1)=28. 2x-3>3x+1. 3^X+4^X=5^X. X+5-2 4-X -X-4 решение. 2x - 5 = 3 решение