$\left \{ {{4x+7y=16} \atop {4x-3y=24}} \right.$
$⇔\left \{ {{4x+7y-(4x-3y)=16-24} \atop {4x-3y=24}} \right.$
$⇔\left \{ {{4x+7y-4x+3y=-8} \atop {4x-3y=24}} \right.$
$⇔\left \{ {{10y=-8} \atop {4x-3y=24}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x-3y=24}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x-\dfrac{-8.3}{10} =24}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x+\dfrac{24}{10} =24}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x+\dfrac{12}{5} =24}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x=24-\dfrac{12}{5}}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {4x=\dfrac{108}{5}}} \right.$
$⇔\left \{ {{y=\dfrac{-8}{10}} \atop {x=\dfrac{27}{5}}} \right.$
