Question

2x - 3y = -18 5x + 3y = 2

Answer 1

Resposta:

$x=-\frac{16}{7}\ e\ y=\frac{94}{21}$

Explicação passo a passo:

$2x-3y=-18\ (i)\\5x+3y=2\ (ii)\\\\\\2x=-18+3y=>x=\frac{-18+3y}{2}\ (iii)\\\\Substituindo\ (iii)\ em\ (ii)\ temos:\\\\5(\frac{-18+3y}{2})+3y=2\\\\\frac{-90+15y}{2}+3y=2\\\\2(\frac{-90+15y}{2}+3y)=2(2)\\\\-90+15y+6y=4\\\\21y=4+90\\\\21y=94\\\\y=\frac{94}{21}\\\\Substituindo\ o\ valor\ de\ y\ em\ (iii)\ temos:\\\\x=\frac{-18+3(\frac{94}{21})}{2}\\\\x=\frac{-18+\frac{282}{21}}{2}\\\\x=\frac{\frac{21(-18)+282}{21}}{2}\\\\x=\frac{\frac{-378+282}{21}}{2}\\\\x=\frac{\frac{-96}{21}}{2}$

$x=-\frac{96}{21}\bullet\frac{1}{2}\\\\x=-\frac{96}{42}\\\\x=-\frac{16}{7}$