X+X+13+[100-(x+13)÷2-X]×3=200
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
(X+X)+(X-X)+(X*X)+(X/X)=100
2x+3x+4x+5x+x+6x+7x=100
若x=π/3,|x+1|+|x+3|+...+|x+13|-|x+2|-|x+4|-...-|x+12|
x+x/3+2x=200
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)
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
解方程((13x-x^2)/(x+1))(x+(13-x)/(x+1))=42
(13x-x^2)/(x+1)[x+(13-x)/(x+1)]=42
计算(x-2)(x-3)+2(x+6)(x-5)-3(x平方-7x+13)