Question

X-3Y=9
4X-3Y=18
METODO SUSTITUCIÓN

Answer 1

SOLUCIÓN

♛ HØlα!! ✌

                              $Despejaremos\:"x"\:de\:la\:primera\:ecuaci\'on\\\\x-3y=9\\\\\\x=9+3y\\\\\\x=9+3y\\\\\\Reemplazamos\:x\:en\:la\:segunda\:ecuaci\'on\\\\\\4x+-3y=18\\\\\\(4)\left(9+3y\right)-3y=18\\\\\\(36+12y)+(-3y)=(18)(1)\\\\\\36+9y=18\\\\\\9y=-18\\\\\\y=\dfrac{-18}{9}\\\\\\\boxed{\boldsymbol{y=-2}}$

                          $Reemplazamos\:"y"\:en\:"x"\\\\\\x=9+3y\\\\\\x=9+3(-2)}\\\\\\x=9-6\\\\\\\boxed{\boldsymbol{x=3}}$