\(\dfrac{a}{b}=\dfrac{c}{d}\Rightarrow\dfrac{a}{c}=\dfrac{b}{d}=\dfrac{a-b}{c-d}\)

\(\Rightarrow\left(\dfrac{a-b}{c-d}\right)^2=\dfrac{a.b}{c.d}\Rightarrow\dfrac{\left(a-b\right)^2}{\left(c-d\right)^2}=\dfrac{ab}{cd}\)

A nha

D

\(\left\{{}\begin{matrix}p+e+n=54\\p+e=n+14\\p=e\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}n+14+n=54\\p=e=\dfrac{n+14}{2}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}n=20\\p=e=17\end{matrix}\right.\)

Please correct the mistake:

a) The cat is among the chair and a television

among => between

b) Sandy are read a books

read => reading

c) She like everyone in your home

like => likes

d) Maye and Mario will gos the cinema all weekend

went

Underlined words đâu?

5. books / the / table / are / Thu’s / on.

=> Thu's books are on the table.

6. lake / house / in / a / live / we / near / a.

=>__We live in a house near a lake___________________________

7.Chi / hair / black / has / long.

=>___Chi has long black hair________________________________________

8. eyes / are / what / his / color / sister’s?

 =>_____What are his sister's eyes color?____________________________

9. and/ classrooms/nice/ very/ our/ are/ new.

=>___Our classrooms are very nice and new____________________________

10. at/ teacher/ teaching/ us/ is/ our/ Maths/ the/ moment.

=>_____Our teacher is teaching us Maths at the moment____________________________ 

\(\left(2y+1\right)\left(1-2y\right)=\left(1+2y\right)\left(1-2y\right)=1-4y^2\)