4x(0.8+x)=7.2, 0.75x+6=2x

4x(0.8+x)=7.2, 0.75x+6=2x x-0.8x=7.2 x-4x=102 x-0.8x=22 x-4x=102x-0.8x=22 X+0.8X=? （X+X)+(X-X)+(X*X)+(X/X)=100 8x-5.5x=7.57.2x÷3.6=2 3x＋6x-8x=0.7 12x-2x-5x=4.512x-x=0 5x＋x=1.8 3.2x＋1.8x=64.8x-0.8x=6 6.3-0.3x=9.6 8.6x-8.5x=0.720x-2x=36 9x＋6x=4.5 18x-12x=5.42x-1.6x=3.6 18x＋3x=7×6 1.2x-0.5x=0.71.3x＋2.7x=1 4x-3.2x=6.4 0.8x＋3.2x＋3x=562.8x-2x=7.2 3.5x+0.5x=12.8 x-0.5x=10.5 0.8x+4=7.2 这些怎么算? 一个“整式的乘法”的问题请先阅读下列解题过程,再仿做下面的问题.已知X*X + X - 1=0,求X*X*X + 2*X*X + 3的值.解X*X*X + 2X*X +3=X*X*X +X*X -X +X*X +X +3=X{X*X +X -1} +X*X +X -1 +4=0+0+4=4+ x + X*X + X*X*X=0.+ X*X + X*X*X x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? 20+0.8x=x-14 112-4x=2x(80-4x) x*x*x*x*x=80000? x-2x+3x-4x+5x.+99x-100x=25求解 先化简,再求值：（x-2/x-x+2/x)/x-2/4x,x=2011 2x+3x+4x+5x+x+6x+7x=100 (x/x-2)+(2/x*2+2x)-(x+6/x*2-4)化简,=x^2/x(x-2)+(2x-4)/x(x^2-4)-(x^2+6x)/x(x^2-4)=x^2/x(x-2)-(x+2)/x(x-2)=(x-2)(x+1)/x(x-2)=(x+1)/x (x-3/x-2)-(x-2/x-1)=(x-5/x4) -(x-4/x-3) x(x+1)+(x+2)+(x+3)+(x+4)+(x+5) = 27求x x-0.75x=4 求x是多少?