1.2x- x-1(分子）/4（分母）-2x+1/5 = 4(x-1)/3 +1
=>x/4-1/4-2x+1/5=4x/3-1/3+1
=>-7x/4-4x/3=1/20-1/3
=>-37x/12=-17/60
=>x=17/185
2.5/11×【11/5×（7/5x +1）-22】- 5/2 = 1/4x
=>7/5x +1-10- 5/2 = 1/4x
=>7/5x -1/4x =23/2
=>23/20x=23/2
=>x=1/10
3.4x+3/4x+1 = 3/4
=>16x^2+4x+3=3x
=>16x^2+x+3=0
=>判别式=1-4*16*3