Question

resolva este sistema pela substituiçao
6x+2y=14
4x+6y=21

Answer 1

$6x+2y=14 \\6x=14-2y \\x= \frac{14-2y}{6} \\ \\4x+6y=21 \\4.( \frac{14-2y}{6} )+6y=21 \\\frac{56-8y}{6}+6y=21 \\ \frac{56-8y+36y}{6}=21 \\56-8y+36y=126 \\-8y+36y=126-56 \\28y=70 \\y= \frac{70}{28}=\frac{10}{4}=\frac{5}{2} \\ou \\y=2,5 \\ \\x= \frac{14-2y}{6} \\x= \frac{14-2.(2,5)}{6} \\x= \frac{14-5}{6} \\x= \frac{9}{6} \\x= \frac{3}{2} \\ou \\x=1,5$