40/30=x+(40/3)/(2/3)x+20咋解呢?

当2x=30x 3x=40x 4x=50x时 那么 x{x+1}{x-1}}x-2}{x-3}-40 60％x+25=40 x+30％x=52 19-120％x=7 4分之3x-5％x=17.5 x-10％x=18 （1-25％）x=36 2x+30％x=9.2 解方程：（x-3)÷2=7.5 3x+x=30 15x+x=40 2.5x-6=18.5 3x+7=59.2 1.（x-3)÷2=7.5 2.3x+x=30 3.15x+x=40 4.2.5x-6=18.5 5.3x+7=59.2 (16x-13)/(4x-3)-(20x-24)/(4x-5)=(32x-30)/(8x-7)-(40x-43)/(8x-9)求x x^3 - 13x^2 + 40x - 40 =0 解分式方程：1/X-2+1/X-6=1/X-7+1/X-11/X-2+1/X-6=1/X-7+1/X-11/(x-2)-1/(x-1)=1/(x-7)-1/(x-6)(x-1-x+2)/(x-2)(x-1)=(x-6-x+7)/(x-7)(x-6)1/(x-2)(x-1)=1/(x-7)(x-6)(x-2)(x-1)=(x-7)(x-6)x^2-3x+2=x^2-13x+4213x-3x=42-210x=40x=4 为什么要移向才能解 11(6-x)/3(x-4)=10(5-x)/3(x-4)-5(6-x)/(x-2)(16x-13)/(4x-3)-(20x-24)/(4x-5)=(32x-30)/(8x-7)-(40x-43)/(8x-9)求x(包括增根) (30-x)/(40-x)=3/5 3/5*(40-x)=30-x X-40%X+1200=2/3X怎么算 3x-40=2(10-x) x+3分之2x=40 x*40%=(12-x)*2/3 x/40-2=X/8+3 (40-2x)/3=15-x x+40%=2x-3