x(x-20)=8000x^2-20x=8000(x-10)^2=8100x-10=90或x-10=-90x=100或x=-80
X=20.0025.按照乘除法运算公式,谁在前面先算谁,则计算出X=20.0025.
x(x-20)-8000=0(x-100)(x+80)=0x1=100x2=-80
8000÷x(x-20)=1x(x-20)=8000x^2-20x-8000=0(x-100)(x+80)=0x1=100 x2=-80