Question

resolva os sistemas:

a) x+ 2y -1
-x+y= -2

b) 2x +3y =5*(4)
3x-4y= -1*(3)

Answer 1

a)

( x+ 2y= -1
( -x+y= -2
---------------
3y= -3
y= -3/3
y= -1

X + 2y= -1
X + 2* (-1)= -1
x -2= - 1
x= -1 + 2
x= 2


b)

( 2x +3y =5*(4)
( 3x-4y= -1*(3)

(2x+3y=20--> 3y= 20-2x
(3x-4y= -3


3x-4y= -3
3x-4*(20-2x) = -3
3x-80+8x= -3
11x= -3 + 80
x= 77/11
x=7

2x+3y=20
2*7+3y=20
14+3y=20
3y=20-14
3y= 6
y= 6/3
y=2


S={(7,2)}