(2/5X-50)+(4/15X-30)+[620-(1/3X-50)-4/15X-30)]=620

*-----------------------------------------------*| 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 || 通分:x+4/x^2-8x+15,x-5/x^2+x-12,x-3/x^2-x-20 x*x+2x+x*x+10x+x*x+25+2x+x*x+1+1+16+x*x+4x*x+9-12x+16x*x+4-16x=30x*x-7x-15 求x,可以只要答案.如图,全是正方形,一个边长为1,一个边长为4,求总面积,你也可以用你的方法.上面那个方程是我列的.5x*X+7X-72=0 计算:[(x+2)/(x+3) - (x+1)/(x+2) + (x+4)/(x+5) - (x+3)/(x+4) / (x^2 + 7x + 13)/(x^2 + 8x + 15) [(x+2)/(x+3)-(x+1)/(x+2)+(x+4)/(x+5)-(x+3)/(x+4)]/[(x的平方+7x+13)/(x的平方+8x+15)] 15X(4X-8)-5X(2X+10)=6X(5X-20) 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550必须用解方程 (2/5X-50)+(4/15X-30)+[620-(1/3X-50)-4/15X-30)]=620 3/4x-20+15/50-2x*x+7/6x+30=0 不等式 x/4-x/5＞1 x/30-x/50≤1/2 通分x+4/x*x+4x与x-5/x(x-5)-2(x-5) x+2/x+1-x+3/x+2-x+4/x+3+x+5/x+4 (x+3x+5x...+2009x)-(2x+4x+6x+...+2010x) x^2+8x+13/x^2+8x+15-x^2+5x+4/x^2+5x+62/x^2+4x+3+2/x^2+8x+15+2/x^2+12x+35 X-X/12-X/7-X/8-X/4-X/20-X/5-30-120-300=50解方程 x^5-x^4+x^3-x^2+x-1 x^6-x^5+x^4-x^2+x-1 求一个数独答案X X X 9 X X X 8 2 X 6 3 X X 1 4 X 99 X 8 X X X X X XX X X 6 7 X 3 X XX 4 6 X 5 X 2 9 XX X 7 X 2 3 X X XX X X X X X 7 X 17 X 4 3 X X 6 2 X6 3 X X X 7 X X X