Question

Rozwiaz uklad równan metoda podstawiania.

Answer 1

a) 3x + y = -3
-x + 3y = 11
y = -3 -3x
-x +3*(-3 -3x) = 11
-x -9 -9x = 11
-10x = 20/: (-10)
x = -2
y = -3 -3x = -3 -3*(-2) = -3 + 6 = 3

b) x - y +2 = 0
2y = x +6
x = y -2
2y = y -2 +6
2y -y = 4
y = 4
x = 4 -2 = 2

c) 3x -2 = 2y
y - 6x = -5/2  |* 2
3x -2 = 2y
2y - 12x = -5
3x - 2 -12x = -5
- 9x = -5 + 2
-9x = -3 / :(-9)
x = 3/9 = 1/3
2y = 3x - 2
2y = 3*1/3 - 2
2y=1-2
2y = -1/: 2
y= -1/2