Use addition or substitution to find the value of x for this set of equations. x + y = 14 x = 6y?

2017-08-17 1:07 am

回答 (5)

2017-08-17 1:12 am

x + y = 14
x - 6y = 0

x + y = 14
-x + 6y = 0
7y = 14
y = 2
x = 14 - 2 = 12
(x, y) = (12, 2)

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2017-08-17 1:19 am

x + y = 14 …… [1]
x = 6y …… [2]

Substitute [2] into [1] :
(6y) + y = 14
7y = 14
y = 2

Put y = 2 into [2] :
x = 6(2)
x = 12

(x, y) = (12, 2)

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2017-08-17 2:20 am

7y = 14
y = 2
x = 12

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2017-08-17 1:34 am

x = 6y
So you can substitute "6y" for "x" in the first equation
"x + y = 14" is the same as "6y + y + 14"
Then it is simple match
7y = 14
y = 2

👍 1 👎 1

2017-08-17 4:21 am

Substitution
6y + y = 14
7y = 14
y = 2
When y = 2
x = 12

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