Rozwiązane

Rozwiąż układy równań dowolną metodą
a) { x-y= - 1 1/2
[ 2x + y = - 1
b) { 2x + y / 3 + y = 4
{x + 3y = 8
c) { x/2 + 3y/5 = 3 1/2
{x- 2y = - 9



Odpowiedź :

Mushriim
a)
x-y = -1,5
2x + y = -1

x = y -1,5
2(y-1,5) + y = -1

x = y-1,5
2y -3 + y = -1

x = y-1,5
3y = 2

x = y-1,5
y = 2/3

x = 2/3 - 3/2
y = 2/3

x = -5/6
y = 2/3

b)
(2x + y)/(3+y) = 4
x + 3y = 8

2x + y = 12 + 4y
x + 3y = 8

x = (12-3y)/2
(12-3y)/2 + 3y = 8

x = (12-3y)/2
12-3y + 6y = 16

x = (12-3y)/2
3y = 4

x = (12-3y)/2
y = 4/3

x = 4
y = 4/3

c)
x/2 + 3y/5 = 7/2
x -2y = -9

5x + 6y = 35
x -2y = -9

x = (35-6y)/5
(35-6y)/5 - 2y = -9

x = (35-6y)/5
35-6y -10y = -45

x = (35-6y)/5
-16y = -80

x = (35-6y)/5
y = 5

x = 1
y = 5