Điều kiện y khác 7
\(\frac{y+5}{7-y}=\frac{2}{-5}\Rightarrow-5\left(y+5\right)=2\left(7-y\right)\Rightarrow-5y-25=14-2y\)
\(\Rightarrow-3y=39\Rightarrow y=-13\)
<br class="Apple-interchange-newline"><div id="inner-editor"></div>y+57−y =2−5 ⇒−5(y+5)=2(7−y)⇒−5y−25=14−2y