5X一2=7X十8

5X一2=7X十8 X十1十4/5X=1十7/8(X-1)十(X一1)怎么算 已知1十x十x^2 十x^3=0,求x十x^2十x^3十x^4+x^5十x^6+x^7十x^8的值 3x十7x十5x一7x=17十18 (7一2X十x平方)一(5十3X一2x平方) 7(x十4)=2(2一x)十3(4x一2) 6(2x一7)=5(x十8)十9 5(1十2x)=3(x一2)十3(17一x) 5x十8=4x一7 2x十5=5x一7= 3x一2十5x—7= 12,5一2x=4x十7, 5（x一2）十8＜6（x一l）十7 4（x十5一7）十2（3一x）=5 x十y+2x十2y一1x十7y= 1/(x^2一4x十3)十1/(x^2一8x十15)十1/(x^2-12x十35)十1/(x^2一16x十63)= 1/2(2X十5)=4x十3/4一2一3x/8,解方程 (x十3)(x一3)十8>(x十5)(x一1)解不等式 5x十2x=42 15十2x一3=48 2x十3x十17=37 6x一3x=6÷5 9x一2x=15x十2x=4215十2x一3=482x十3x十17=376x一3x=6÷59x一2x=1.4十0.077(2x一6)=15.4 3(2x一1)十5(1一2x)十2x十4=0怎么解