Question

Решите систему уравнений методом подстановки:
4x-9y=3
x+3y=6

Answer 1

$left { {{4x - 9y = 3} atop {x+3y=6}} right. left { {{4x - 9y = 3} atop {x=-3y+6}} right. left { {{4(-3y+6) - 9y = 3} atop {x=-3y+6}} right. left { {{-21y + 21 = 0} atop {x=-3y+6}} right. left { {{y=1} atop {x=-3y+6}} right. left { {{y=1} atop {x=3}} right. ( 3 ; 1 )$

Answer 2

4x - 9y = 3
x + 3y = 6 

4x - 9y = 3 
x = 6 - 3y

4(6 - 3y) - 9y = 3 
x = 6 - 3y

24 - 12y - 9y = 3
x = 6 - 3y

24 - 21y = 3
x = 6 - 3y

y = 1
x = 6 - 3y = 6 - 3*1 = 3 

Ответ:
( 3; 1)