42÷[(38.7十X)÷2]=45,

42÷[(38.7十X)÷2]=45, 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 (x十2)÷0.8=12.5 (x十3)÷2=7.5 怎样计算“x十x÷3十2x一30=180” x÷2十20=75%x 2X十3÷8X=28 一次一元方程 7x十8x十4y=0十8÷-4 化简求值x^2十2x十1/x十2÷x^2-1/x-1-x/x十2,x竽等于根号3 已知x、y的值满足等式(x+1)÷2=(y+3)÷4=(x+y)÷5,求式子(3x十2y十1)÷x十2y十3的值 X.(X十1)x(X十2)x(x十3) =360 1十2十3十4十5十6X5十6十5十4十3十2十1÷6 当a取一实数值时,能使得X有唯一实数值满足等式(x十1)÷(x一1)十(x一1)÷(x十1)十(2x十a十2)÷(x2一1)=0,试这样的实数a的和. 2x十8十3x十8十4x十8=?请算出这道题目求士寸佰了⑥ 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 {6+x十y十7二55,6十2x十5y十70=274 x^2十2x十1=4 2(x十3)=3(0.5x十10)