x/50-(x/5÷50+4x/5÷80)=3怎么解 一步一步的列

解方程：（1）2x-19=7x+31 (2)20-2x=x-1 (3)19-x=100-10x (4)1/3x+5=2/3x-62x-19=7x+317x-2x=-19-31这里应该是31+19吧？5x=-50x=-50÷5x=-10 *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || 解方程,5%x-7.5%x=22.5 25%x-7%x=36 2.3%x+x%=6.6 x-30%x=1.4 x÷50%=10 65%x-25%x=8 化简：[(x+2)/(x^2-4)-(2x-5)/(x-4x+4)]÷[(x-3)/(x-2)] X-X/12-X/7-X/8-X/4-X/20-X/5-30-120-300=50解方程 1.(x^3-x^2-4x+1)/(x^2-3x+2)-(x^3-2x^2-9x+21)/（x^2-5x+6）+（x^2-3x+8）/（x^2-4x+3）2.{(x^2)/（x-y)}*{y/(x+y)}-{(x^4y)/(x^4-y^4)}÷{（x^2/x^2+y^2）^2} (1) （x+960）×80％＝x-832 (2) (2x-3)÷7＝59-2x (3) 75％x+40％×(14-x)＝...(1) （x+960）×80％＝x-832(2) (2x-3)÷7＝59-2x(3) 75％x+40％×(14-x)＝50％×14(4) 3/5x＝(x+10)×3/5(5) 1/2+1/6+1/12+1/20+1/30+1/42 5*4x+x*x=80 8x^2-4x/x^2-x-6÷(x-3/x+2-x+2/x-3),其中x=5 16-x^2/x^2-2x-3÷1^2-5x+4/x-3 (16x^4-5x³+3x²-6x)÷(-2x) 使代数式x+3/x-3÷x+5/x-4有意义的x的值 化简：2|x| -3x÷|2x-|5x|| (-x)^5÷x^2 (x+3)(x-4)(x+5)(x-6)+80因式分解 (x-3)(x+4)(x-5)(x+6)+80因式分解 (x+3)(x-4)(x+5)(x-6)+80因式分解, =(x^2-5x)^2+10(x^2-5x)+24 =x^4-10x^3+25x^2+10x^2-50x+24 这是怎么转化的(X-1)(X-2)(X-3)(X-4) =(X-1)(X-4) (X-2)(X-3)=（x^2-5x+4)(x^2-5x+6)=(x^2-5x)^2+10(x^2-5x)+24=x^4-10x^3+25x^2+10x^2-50x+24=x^4-10x^3+35x^2-50x+24