Question

Questão 1- resolva os seguintes sistemas.
A)(×=5y. B)(×=3y. C)(×+y=5
(×+3y =16. (2×+4y=40 (2×-y=4

D)(×+y=7
(×-y=1

Answer 1

A)
x = 5y          
x + 3y =16   

x = 5y
x + 3y = 16
5y + 3y = 16
8y = 16
y = 16/8
y = 2

x = 5y
x = 5.2
x = 10

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B)
x = 3y           
2x + 4y = 40   (:2)     
x + 2y = 20

x = 3y
x + 2y = 20
3y + 2y = 20
5y = 20
y = 20/5
y = 4

x = 3y
x = 3.4
x = 12
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c)
x + y = 5
2x - y = 4  (+)
-------------------
3x = 9
x = 9/3
x = 3

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

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d) 
x + y = 7
x - y = 1   (+)
----------------------
2x = 8
x = 8/2
x = 4

x + y = 7
4 + y = 7
y = 7 - 4
y = 3