18X=19.8
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x加30%x=521.3x=52x=52×1.3x=40x减40%x=150.6x=15x=15÷0.6x=2550%x加x=31.51.5x=31.5x=31.5÷1.5x=21x减1%x=19.8
3x-18=13.23x=13.2+18x=10.41.5x-x=60.5x=6x=6/0.5=124x+1.2x=265.2x=26x=5
原式:X^2-5X+6+18=X^2+10X+9-5X+24=10X+915X=15X=1
(X-X*20%-18)-(X-X*20%-18)*10%=X*1/2-3则(X*80%-18)*90%=X*1/2-372%*X-16.2=X*1/2-322%*X=13.2X=60
19.8x+0.2x=2.5×2⇒ (19.8+0.2)X=5⇒ 20X=5⇒ X=0.25
X=10啊,只有这一个结果吧
x-0.2x=180.8x=18x=18÷0.8x=22.5
1/x(x+3)+1/(x+3)(x+6)+1/(x+6)(x+9)=3/2(x+9)(1/3)×[3/x(x+3)+3/(x+3)(x+6)+3/(x+6)(x+9)]=3/2(x+9)(1/3)[
(X+X)+(X-X)+(X*X)+(X/X)=1002X+0+X*X+1=1002X+X*X=99X(X+2)=99X=9再问:请问X(X+2)=99解为什么就等于9了呢没看懂再答:换成算术法你就明
x-1%x=19.80.99x=19.8x=19.8/0.99x=20x-40%x=150.6x=15x=15/0.6x=25x+25%x=2.51.25x=2.5x=2.5/1.25x=250%x+
x(x-1)=18x-x=18x-x+1/4=18+1/4(x-1/2)=73/4x=1/2±√73/2
10(x+2)+x-18=10x+x+2x11x+2=13x2x=2x=1
x^4-4x^3-4x^2+15x+18=0x^4-3x^3-x^3+3x^2-7x^2+21x-6x+18=0(x-3)(x^3-x^2-7x-6)=0x1=3x2=3.49449283705542
0.3X=18X=60
设x1=4-√3,x2=4+√3,是方程X^2-8X+13=0的两根所以X1^2-8X1+15=2X^4-6X^3-2X^2+18X+23=(X+1)^2*(X^2-8X+13)+10=10所以原式=
1/[x(x+3)]+1/[(x+3)(x+6)]+.+1/[(x+15)(x+18)]=1/3[1/x-1/(x+3)]+[1/(x+3)-1/(x+6)]+.+[1/(x+15)-1/(x+18)
1/x(x+3)+1/(x+3)(x+6)+1/(x+6)(x+9)=[1/x-1/(x+3)+1/(x+3)-1/(x+6)+1(x+6)-1/(x+9)]/3=[1/x-1/(x+9)]/3=3/
x/(x+3)-x/(3-x)=18/(x平方-9﹚x/﹙x+3﹚+x/﹙x-3﹚=18/﹙x+3﹚﹙x-3﹚x﹙x-3﹚+x﹙x+3﹚=182x²=18x=±3
(5+1)X=186X=18X=3
问题是不是X2=(X+30)*(X-18)啊?要是上面的话就这样X2=X*X-X*18+30*X-30*18=X2+12X-540移项得:X2-X2-12X=-540,即-12X=-540,X=45*