5/8+3/4*(84-x)=57 求x的值,麻烦顺便教教我解的过程.

如果1+x+x^2+x^3=0,求x+x^2+X^3+x^4+x^5+x^6+x^7+x^8的值, 已知x=2π+1求 |x-1|+|x-2|+|x-3|+|x-4|+|x-5|+|x-6|+|x-7|+|x-8|+|x-9|+|x-10| 已知x=2π+1.求(X-1)+(X-2)+(X-3)+(X-4)+(X-5)+(X-6)+(X-7)+(X-8)+(X-9)+(X-10) 设x= -5/2,求6x+(x/x-2 - x/x+2)/4x/x^4-2x^3+8x-16的值 1X?+2X?+3X?+4X?+5X?+6X?+7X?+8X?+9X?+10X?=1980求?是多少 x(x+1)+(x+2)+(x+3)+(x+4)+(x+5) = 27求x (6x-12)(8x+5)=(4x-3)(6x-12)求x x-4/x-5 - x-5/x-6=x-7/x-8 - x-8/x-9求x=? 已知x^5+x^4-5x^3-2x^2+4x-8 求x+1/x已知x^5+x^4-5x^3-2x^2+4x-8 求x+1/x出错了!已知x^4-5x^3+8x^2-5x+1=0 求x+1/x 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 (16x-13)/(4x-3)-(20x-24)/(4x-5)=(32x-30)/(8x-7)-(40x-43)/(8x-9)求x X+2分之X+3-X+4分之X+5=X+6分之X+7-X+8分之X+9,求X的值 4x的平方+15x-5=0,求（-15x*x-18x+9)-(-3*x*x+19x-31)-8x matlab中a(x)=x^4+3x^3+9x-18 b(x)=x^5-4x^3-18x+7 c(x)=x^7+6x^5+9x^3-5x^2-2 d(x)=x^9-8x^7+6x^5-4x^4+d(x)=x^9-8x^7+6x^5-4x^4+6x^2+3 求e(x)=a(x)*b(x)*c(x)*d(x) 已知2^x+2^-x=5 (1)求4^x+4^-x (2) 8^x+8^-x 3Q 已知x^4-5x^3+8x^2-5x+1=0 求x+1/x 求方程解x-5/x-4+x-9/x-8=x-8/x-7+x-6/x-5 x-4／x-5-x-5／x-6=x-7／x-8-x-8／x-9求大神帮助