[x(1-50%)-1600-100]*(1-25%)/500=[x(1-50%)-1820]*(1-25%)/400,
x除55%=100 60%x=30 x+50%x=4.5 (1-25%)x=72 4x+40%x=176 解方程
x加30%x=52、x减40%x=15、50%x加x=31.5、x减1%x=19.8、x加25%x=2.5、x减15%x
x-1)(X-2)(x-3)...(x-50)+x(x-2)(X-3)...(X-50)+...+x(x-1)(x-2)
1/2x+1=1/2-1/3x x-2x+3x-4x+...+99x-100x=25
x*x+2x+x*x+10x+x*x+25+2x+x*x+1+1+16+x*x+4x*x+9-12x+16x*x+4-1
解方程:(2x+5)(4x*x-10x+25)=8x(x*x+1)
25%x+(1-25%)*20%x+6=x
X^2+(X+1)^2=25 X=?
X+(3X-16)÷25%=10(x+1)
1X+2X+3X…+98X+99X+100X=50500X X等于多少?
1x+2x+3x+4x+5x+6x+7x…+99x=100
解方程:2x+4x+6x...+100x=1-(x+3x+5x+...+99x)