Question

resolva os sistemas
a) x-y=1
x+2y=22

b) x+7y=200
x-11y=2


c) 2x+y=0
5x-2y=45

Answer 1

x-y=1    [-1] para cortarmos o x
x+2y=22

-x +y = -1
x + 2y = 22
0x +3y = 21
y = 21/3
y = 7

x - 7 = 1
x = 7 +1
x = 8

b) x+7y=200 [-1] para cortar o x
x-11y=2

-x -7y = -200
x - 11y = 2
0x -18y = -198
-18y = -198 [-1]
18y = 198
y = 198/18
y = 18

-x +7.18 = 200
-x + 136 = 200
-x = 200 - 136
-x = 64  [-1
x = -64

c) 2x+y=0 [2] para cortar o Y
5x-2y=45

4x + 2y = 0
5x - 2y = 45
9x + 0y = 45
9x = 45
x = 45/9
x = 5

2.5 + y = 0
10 + y = 0
y = -10