Question

resolva a equação
x+2y=7
x+y=4

Answer 1

Resposta:

$x+2y=7~....~equacao~I\\x+~y=4~....~equacao~II\\ \\multiplique~uma~das~equacoes~por~(-1)~para~eliminar~uma~incognita\\utilizando~o~metodo~da~adicao\\\\x+2y=7~~.(-1)\\ \\~~~~~~~~-x-2y=-7~...~equacao~I\\+~~~~~~~~x+~y=~~4~...~equacao~II\\~~~~~~~~-------\\~~~~~~~~~~~~0-~y=-3\\ \\y=3\\ \\substitua~(y=3)~em~uma~das~equacoes\\ \\equacao~II\\ \\x+y=4\\ \\x+3=4\\ \\x=4-3\\ \\x=1\\ \\resposta:\\ \\S~~\left \{ {{y=3;~~x=1} \}} \right.$