500*5%+1500*10%+(x-2000)*15%=250 算哈
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
4x-3(x-5)=2x+(x-1) (3x+29)除以8=4x 7(x+10)=5(4x-10) 5分之2(x-15)
(2x-2)(x-1)=0 x(x-5)=5x-10
解方程.(5x/x²+x-6)+(2x-5/x²-x-12)=7x-10/x²-6x+8
500*20%+5%x=(500+x)*15/%
若1+x+x*x+x*x*x=0,求x+x*x+x*x*x+.+x(2000次幂)
1)x+1/x=3,求x^10+x^5+1/x^5+1/x^10的值
解方程:(0.3-X)(500+10X)=120:;(44-X)(20+5X)=1600
x的平方-2x+1=15 ; x(2x-5)=4x-10 ; x的平方+5x+7=3x=11
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
(x-6)/(x-5)-(x-7)/(x-6)=(x-9)/(x-8)-(x-10)/(x-9)
计算:1/(x^2-7x+10)+1/(x^2-x-2)+1/(x^2+5x+4)+1/(x^2+11x+28)=( )