Question

Resolva os sistemas de equação

1) {a-b=7
1) {a+b=13

2) {x-2y=16
2) {-x+8y=32

Answer 1

1) a - b = 7 Adiçao


a + b = 13
________
2a = 20
a = 20/2
a = 10

2) x - 2y = 16 ( 4 )
- x + 8y = 32

4x - 8y = 64
- x + 8x = 32
___________
3x = 96
x = 96/3
x = 32

substituiçao
1) a - b = 7
a + b = 13
a= 7 + b

a + b = 13
1 ( 7 + b ) + b = 13
7 + b + b = 13
7 + 2b = 13
2b = 13 - 7
2b = 6
b = 6/2
b = 3

2) x - 2y = 16

x = 6 + 2y = 16

- x + 8x = 32
- 1 ( 6 + 2y) + 8y = 32
- 6 - 2y + 8y = 32
6y = 32 + 6
6y = 38
y = 38/6 simplificando pir 2
19/3