Question

alguem me ajuda a resolver essa equação do 1 grau pelo método da substituição?

3X+20+X+40=180
X+40=y

preciso aprender como resolve, tenho prova amanhã a tarde ​

Answer 1

Ola!!!

$\left\{\begin{array}{cc}3x+20+x+40=180\\x+40=y\\\end{array}\right$
$\left\{\begin{array}{cc}3x+x=180-20-40\\x-y=-40\\\end{array}\right$

$\left\{\begin{array}{cc}4x=120\\x-y=-40\\\end{array}\right$

$\left\{\begin{array}{cc}x=30\\x-y=-40\\\end{array}\right\:\left\{\begin{array}{cc}x=30\\30-y=-40\\\end{array}\right\:\left\{\begin{array}{cc}x=30\\-y=-40-30\\\end{array}\right\:\:\left\{\begin{array}{cc}x=30\\-y=-70\\\end{array}\right\:\:\left\{\begin{array}{cc}x=30\\y=+70\\\end{array}\right$

$S=\{30\:\:;\:\:70\}$

$\underline{Qualquer\:Dúvida\:Comente}$