15*0.9 (x-15)*3

照相机

=x^18+x^15+x^12+x^9+x^6+x^3+1+x^3-1+5-4分解因式把下面的18换成21就是了=(x^18+1)+(x^15+1)+(x^12+1)+(x^9+1)+(x^6+1)+

1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550120x=550x=55/12=4.583

[(X+3)/(X^2-4)-(-X)/(6-X-X^2)]/[1-(X^2-3X-15)/(X^2+X-6)]={(x+3)/[(x+2)(x-2)]-x/[(x+2)(x-3)]}/[(4x+9)

2x^3-x^2-15x>0x(2x+5)(x-3)>0-5/2

原式=[(1-1分之x+5)-(1-1分之x+4))+(1-1分之x+3)-(1-1分之x+2)]*[(x+3)(x+5)]\(x^2+7x+13)=[(1分之x+2)-(1分之x+3)+(1分之x+

x-3分之2x=153分之1x=15x=15÷3分之1x=15×3x=45再问：5（x减6.8）等于10.5求x是多少再答：5（x-6.8）=10.55x-5×6.8=10.55x-34=10.55x

x(x^2-6x-9)-x(x^2-8x-15)+2x(3-x)=x^3-6x^2-9x-x^3+8x^2+15x+6x-2x^2=12x=36

X(X^2-6X-9)-X(X^2-8X-15)+2X(3-X)=X^3-6X^2-9X-X^3+8X^2+15X+6X-2X^2=12x带入X=1/3原式=12*1/3=4

x/2（1/1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)=1x/2*10/11=110x=22x=11/5这回的方法是你想要的了吧

10-3x=410-4=3x6=3x∴x=20.9x=8.1x=915x-7.5x=157.5x=15x=20.8x+0.4x=1.21.2x=1.2x=1

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)

(x+1)(x+3)(x+5)(x+7)+15=[(x+1)(x+7)][(x+3)(x+5)]+15=(x^2+8x+7)(x^2+8x+15)+15=(x^2+8x+7)[(x^2+8x+7)+8

(4x+20)(x的平方-6x+9)/(3x-x的平方)(x的平方+2x-15)=4(x+5)(x-3)²/3（3-x）(x-3)(x+5)=-4/3

原式=[(x²+2)-3x][(x²+2)-x]-15x²=(x²+2)²-4x(x²+2)+3x²-15x²=(x&#

(x+1)(x+3)(x+5)(x+7)+15=(x+1)(x+7)（x+3）（x+5）+15=(x²+8x+7)(x²+8x+15)+15=(x²+8x)²+

1/2x－28=501/2x=50+28=78x=156x－2/7x=15/285x/7=15/28x=3/43x－1.2=3.63x=3.6+1.2=4.8x=1.6x－20％x=7.280%x=7

x^3+x-30(分解因式)=(x^3-27)+(x-3)=(x-3)(x^2+3x+9)+(x-3)=(x-3)(x^2+3x+9+1)=(x-3)(x^2+3x+10);x^12-y^12;=(x

2x等于x+15x等于15