Question

28*X44*(0.4-X)=16.

Answer 1

28*X44*(0.4-X)=16.8

左边开括号,得

28x*44*0.4-28x*44*x=16.8

左边化简,得

492.8x-1232x^2=16.8

两边乘以-1并加上16.8,得

1232x^2-492.8x+16.8=0

方程两边同时约去5.6,

得,220x^2-88x+3=0

配方,得220（x-1/5）^2-29/5=0

有（x-1/5）^2=29/1100

两边开方得x=[2+根号（29/11）]/10或者[2-根号（29/11）]/10