Question

Resolva pelo metódo de adição:

A) x+y=-7

x-y=6

B) m+n=4

3m+n=2

C)a-3b=10

5a+b=34

D) 2x=5+3y

y=4-7x

Answer 1

a) x + y = - 7
x - y = 6
_________
2x = - 1
x= -1/2

b) m + n = 4 ( - 1 )
3m + n = 2
- m - n = - 4
3m + n= 2
_______
2m = - 2
m = -2/2
m= -1
c) a - 3b = 10
5a + b = 34 ( 3 )
___________
a - 3b = 10
15a - 3b = 102
_____________
16a= 112
a = 112/16
a = 7

d) 2x-3y = 5
7x + y = 4 (3 )


2x -3y = 5


21 x + 3y = 12
__________
23x = 17
x = 17/23