Question

sistema de equacoes com o metodo da substituição
a) {3x + 2y = 3
{ x - y = 4​

Answer 1

$\left \{ {{3x+2y=3} \atop {x-y=4}} \right.$

$\left \{ {{3x+2y=3} \atop {x=4+y}} \right.$

$3x+2y=3$

$3(4+y)+2y=3$

$12+3y+2y=3$

$3y+2y=3-12$

$5y=-9$

$y=-\frac{9}{5}$

$x=4+y$

$x=4+(-\frac{9}{5})$

$x=4-\frac{9}{5}$

$x=\frac{20}{5}-\frac{9}{5}$

$x=\frac{11}{5}$