x-0.3x=4.9怎么解

x-0.3x=4.9怎么解 0.3x+0.3x+14+28=x怎么解? 方程：0.5x+140+0.3x=x怎么解 x*x-x=90怎么解 x^2=(x+30)X(x-18)怎么解 x 5x=21.6-x-5x怎么解 (x+12)*(x+12)=x*x+360怎么解 x-(30-x)=(30-x)-x/3,怎么解 x*x=(x+10)*(x-6)怎么解 x(x+x)=48 求x 怎么解 (x+x+23+x+50)=3x 怎么解 x*x=75%x*(x+3)怎么解? (168+X)/(288+X)=(120-X)/X怎么解 x*x+2*x+1=36,x怎么解, x(x+1)-x(x-1)=188怎么解, 25%X+(144-x)=x-25%X怎么解 x(x+1)-x(x-1)=188怎么解, (x+3)*(x+3)-x*x=81怎么解