Question

Resolva As Equações.

a) x+y=5
x-y=1

b) x-3=y
-2x+5y=13

c) x-y=5
x+y=7

d) x-y=2
x+y=7

e) x-y=1
x+y=9

Answer 1

A) x+y=5 ( -1 )
. x-y=1

-x-y= -5
x-y= 1

-2y= -4
y= -4/-2
y=2

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

B) x - 3=y
.-2x+5y=13

x - y =3 (2)
-2x+5y=13

2x - 2y=6
-2x+5y=13

3y=19
y=19/3
y= 6,33

-2x+5y=13
-2x+5.6,33=13
-2x+31,65=13
-2x=13 - 31,65
-2x= -18,65
x= -18,65/-2
x= 9,33

C) x - y =5
. x+y=7

2x=12
x=12/2
x=6

x - y =5
6 - y =5
-y=5 - 6
-y= -1
y= -1/-1
y= 1

D) x - y =2
. x + y =7

2x=9
x=9/2
x= 4,5

x - y =2
4,5 - y =2
-y=2 - 4,5
-y= -2,5
y= -2,5/-1
y=2,5

E) x - y =1
. x + y =9

2x=10
x=10/2
x=5

x - y = 1
5 - y = 1
-y =1 - 5
-y= -4
y= -4/-1
y=4