tính giá trị biểu thức sau biết abc=2016
P= $\dfrac{2bc-2016}{3c-2bc+2016}-\dfrac{2b}{3-2b+ab}+ \dfrac{4032-3ac}{3ac-4032+2016a} $
tính giá trị biểu thức sau biết abc=2016 P= $\dfrac{2bc-2016}{3c-2bc+2016}-\dfrac{2b}{3-2b+ab}+ \dfrac{4032-3ac}{3ac-4032+2016a} $
By Rylee
Đáp án+Giải thích các bước giải:
`*){2bc-2016}/{3c-2bc+2016}=-1+{3c}/{3c-2bc+2016}`
`*){-2b}/{3-2b+ab}={-2bc}/{3c-2bc+abc}={-2bc}/{3c-2bc+2016}`
`*){4032-3ac}/{3ac-4032+2016a}=-1+{2016a}/{3ac-2abc+2016a}`
`=-1+{2016}/{3c-2bc+2016}`
`⇒P=-1`
Ta có :
`+)`
`(2bc-2016)/(3c-2bc+2016)=(3c-2bc+2016-3c)/(3c-2bc+2016)=-1+(3c)/(3c-2bc+2016)`
`+)`
`(-2b)/(3-2b+ab)=(-2bc)/(3c-2bc+abc)=(-2bc)/(3c-2bc+2016)`
`+)`
`(4032-3ac)/(3ac-4032+2016a)=(3ac-2abc+2016a+2016a)/(3ac-2abc+2016a)=-1+2016/(3a-2bc+2016)`
`to P=-1+(3c)/(3c-2bc+2016)+(-2bc)/(3c-2bc+2016)-1+2016/(3a-2bc+2016)`
`to P=-2+(3c-2bc+2016)/(3a-2bc+2016)`
`to P=-2+1=-1`