www.qprq.net > X+1/X+2+X+6/X+7=X+5/X+6+X+2/X+3 简便方法

X+1/X+2+X+6/X+7=X+5/X+6+X+2/X+3 简便方法

[(x+1)/(x+2)]-[1/(x+7)]=[(x+2)/(x+3)]-[1/(x+6)] 为简化起见,特设:(x+1)=a,(x+2)=b,(x+3)=c,(x+6)=d,(x+7)=e 于是公式成为:a/b-1/e=b/c-1/d 先移项:a/b-b/c=1/e-1/d 等式两边同乘以:bcde,也就是同乘(x+2)(x+3)(x+6)(x+7) 得:de(ac-bb)=bc(d-e)...

x+x-3分之n的2次方+n=2n+4 x-3+(x-3)分之n²+n=2n+4-3 x-3+(x-3)分之n²+n=2n+1 令x-3=t t+t分之n²+n=2n+1 解得t=n或t=n+1 即x-3=n或x-3=n+1 得x=n+3或x=n+4

1/9{1/7[1/5(1/3(x+2)+4)+6]+8}=1 1/7[1/5(1/3(x+2)+4)+6]+8=9 1/7[1/5(1/3(x+2)+4)+6]=9-8 1/5(1/3(x+2)+4)+6=7 1/5(1/3(x+2)+4)=7-6 1/3(x+2)+4=5 1/3(x+2)=5-4 x+2=3 x=1

(1)1.7x+130%x=6 3x=6 3x÷3=6÷3 x=2;(2)13-20%x=8 13-20%x+20%x=8+20%x 8+20%x=13 8+20%x-8=13-8 20%x=5 20%x÷20=5÷20% x=25;(3)37x-514x=70% 114x=70% 114x×14=70%×14 x=9.8.

方程式为(x+4n-2)╱x=2n+2解为(n+1)╱2 6是2加4乘1,12为2加4乘2,第n个数为2加4乘(n-1) 放程式解为2乘1╱2,3乘1╱2,4乘1╱2,第n个解为(n+1)乘1╱2

原式 =1x2x3(1+3+7)/[(1x3x5) (1+3+7)] =6/11

1/(x+5)+1/(x+8)=1/(x+6)+1/(x+7) 1/(x+5)-1/(x+6)=1/(x+7)-1/(x+8) {(x+6)-(x+5)}/{(x+5)(x+6)} = {(x+8)-(x+7)}/{(x+7)(x+8)} 1/{(x+5)(x+6)} = 1/{(x+7)(x+8)} (x+5)(x+6) = (x+7)(x+8) x²+11x+30 = x²+15x+56 11x-15x=56-30 -4x=2...

4.2x6.7+6.7x1.2+3.3x5.4 =6.7x(4.2+1.2)+3.3x5.4 =6.7x5.4+3.3x5.4 =5.4.x(6.7+3.3) =5.4.x10 =54

7/(x²+x)+3/(x²-x)=6/(x²-1) 解: 7/x(x+1)+3/x(x-1)=6/(x+1)(x-1) 7(x-1)+3(x+1)=6x 7x-7+3x+3=6x 4x=4 x=1 检验:因为当x=1时,x2-1=0 所以x为增根, 所以原方程无解。 基本步骤就是这样的,不懂追问,懂了望采纳

先求它们的倒数和,再把结果倒回来。 1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9+9x10+10x11 =10×(10+1)×(10+2)÷3 =10×11×12÷3 =110×12÷3 =1320÷3 =440

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