Question

Solve by substitution -2x+4y+6=0 x-5y+3=0

Answer 1

$-2x+4y+6=0 \\ x-5y+3=0 \\ \\ \hbox{solve the 1st equation for x:} \\ -2x+4y+6=0 \ \ \ |-(4y+6) \\ -2x=-4y-6 \ \ \ |\div (-2) \\ x=2y+3 \\ \\ \hbox{substitute 2y+3 for x in the 2nd equation:} \\ 2y+3-5y+3=0 \\ -3y+6=0 \ \ \ |-6 \\ -3y=-6 \ \ \ |\div (-3) \\ y=2 \\ \\ x-5y+3=0 \\ x-5 \times 2+3=0 \\ x-10+3=0 \\ x-7=0 \ \ \ |+7 \\ x=7 \\ \\ (x,y)=(7,2)$