Biết a+b+c=2p.CMR:\(\dfrac{1}{p-a}+\dfrac{1}{p-b}+\dfrac{1}{p-c}-\dfrac{1}{p}=\dfrac{abc}{p\left(p-a\right)\left(p-b\right)\left(p-c\right)}\)

Cho các số thực a,b,c,d thoả mãn:\(\left\{{}\begin{matrix}a+b=c+d\\ab+1=cd\end{matrix}\right.\).CMR:c=d

Cho \(a^2+a+1=0\).Tính giá trị biểu thức \(P=a^{2019}+\dfrac{1}{a^{2019}}\)

Choose the letter A, B, C or D the word that has the underlined part different from others.

A. scream      

B. mean      

C. spread      

D. meal

Lan (buy) some new clothes tomorrow?