Question

x-7 phan y-6 =7 phan 6 va x - y= -4

Answer 1

 \(\frac{x-7}{y-6}=\frac{7}{6}\) và x - y = -4

Cách 1: x - y = -4 => x = (-4) + y => x = -4 - y

Thay x = 4 + y vào ta có :

\(\frac{-4-y-7}{y-6}=\frac{7}{6}\)

=> \(\frac{-4-7-y}{y-6}=\frac{7}{6}\)

=> \(\frac{-11-y}{y-6}=\frac{7}{6}\)

=> \(6\left(-11-y\right)=7\left(y-6\right)\)

=> \(-66-6y=7y-42\)

=> \(y=-\frac{24}{13}\)

Lại có : x = -4 - y => x = \(-4-\left(-\frac{24}{13}\right)=-\frac{28}{13}\)

Vậy \(\left(x,y\right)\in\left(-\frac{24}{13},-\frac{28}{13}\right)\)

Answer 2

\(\frac{x-7}{y-6}=\frac{7}{6}\)và \(x-y=-4\)

\(x-y=-4\Rightarrow x=-4+y\)

\(\frac{-4+y-7}{y-6}=\frac{7}{6}\)

\(\frac{-11+y}{y-6}=\frac{7}{6}\)

\(\Rightarrow\left(-11+y\right).6=\left(y-6\right).7\)

\(\Rightarrow-66+y.6=y.7-42\)

\(\Rightarrow y6-y7=-42+66\)

\(\Rightarrow-y=24\Rightarrow y=-24\)

Vì \(x=-4+y\)

\(\Rightarrow x=-4-24=-28\)

Vậy \(\left(x;y\right)=\left(-28;-24\right)\)