Răspuns:
Explicație pas cu pas:
a)
2x - y = 1
x + 2y = 8
y = 2x - 1
x + 2(2x - 1) = 8
x + 4x - 2 = 8
5x = 8 + 2 = 10
x = 10 : 5 = 2
y = 2*2 - 1 = 4 - 1 = 3
_______________
b)
3x + 2y = 8
x + 2y = 6
x = 6 - 2y
3(6 - 2y) + 2y = 8
18 - 6y + 2y = 8
18 - 8 = 4y
4y = 10
y = 10/4 = 5/2
x = 6 - 2*5/2 = 6 - 5 = 1
___________________
c)
2x - y = 3
x + 2y = 6
4x - 2y = 6
x + 2y = 6
5x = 12
x = 12/5
y = 2x - 3 = 24/5 - 15/5 = 9/5
_____________________
d)
3x - 2y = 4
2x + 4y = 8
6x - 4y = 8
2x + 4y = 8
8x = 16
x = 16 : 8 = 2
2y = 3x - 4 = 6 - 4 = 2
y = 2 : 2 = 1
