Question

Resolva os sistemas:

A) 3x+2y = 2
2x+3y = -1

B)5x-3y = 9
4x+2y = 4

Answer 1

A)
3x+2y= 2 (2)
2x+3y= - 1 (-3)

6x +4y= 4
-6x -9y =3(+)
----------------------
-5y = 7 (-1)
5y=-7
Y = -7/5

3x+2y= 2
3x+2.(-7/5) = 2
3x - 14/5 = 2
3x = 2 + 14/5
15x/5= (10 + 14)/5
15x=24 (:3)
5x = 8
X = 8/5
B)

5X-3y=9
4x+2y=4 (:2)

5X-3y=9
2x+y=2 (.3)

5X-3y =9
6x+3y=6 (+)
---------------
11x=15
x = 15/11
2x + y = 2
2.15/11 +y = 2
30/11 +y = 2
(30+11y)/11 = 22/11
30+11y= 22
11y = 22-30
11y= -8
y = -8/11