Question

4x=3y với x+y=14

tìm x,y

Answer 1

\(\left\{{}\begin{matrix}4x=3y\\4x+4y=4\cdot14=56\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x=3y\\3y+4y=56\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x=3y\\y=8\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=6\\y=8\end{matrix}\right.\)

Answer 2

\(4x=3y=>y=\dfrac{4x}{3}\) thế y vào x+y=14

\(=>x+\dfrac{4x}{3}=14< =>\dfrac{7x}{3}=14=>7x=42< =>x=6\)

\(=>y=\dfrac{4.6}{3}=8\)

Answer 3

4x=3y tương đương x/3=y/4

Áp dụng.............

x/3=y/4=x+y/3+4=14/7=2

Answer 4

Ta có: \(\left\{{}\begin{matrix}4x-3y=0\\x+y=14\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x-3y=0\\4x+4y=56\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-7y=-56\\x+y=14\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}y=8\\x=6\end{matrix}\right.\)

Answer 5

x/3=2 

x=6

y/4=2

y=8

Vậy

Answer 6

4x=3y=>x/3=y/4

Tính chất của dãy tỉ số bằng nhau : x/3 + y/4 = (x+y)/(3+4)=14/7=2

=>x=6 : y=8