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5x +2y=22
4x+y=17
In the system of equations above, what
is the value of x+y?
A. 5 B. 4 C. 3 D. 2

Respuesta :

phamthuylinh345183

Answer:

A: 5

Step-by-step explanation:

4x + y = 17 --> y = 17 - 4x

5x + 2y = 22

<=> 5x + 2 . (17 - 4x) = 22

<=> 5x - 8x + 34 = 22

<=> 34 - 3x = 22

<=> 3x = 34 - 22 = 12

<=> x = 4

y = 17 - 4x = 17 - 4 . 4 = 17 - 16 = 1

So, x + y = 4 + 1 = 5

Answer: A. 5
Step 1: solve for y in 2nd equation
Y=-4x+17
Step 2: sub into first equation
5x+2(-4x+17)=22
Step 3: solve for x
5x-8x+34=22
-3x=-12
x=4
Step 4: plug x=4 into either equations
5(4)+2y=22
Step 5: solve for y
20+2y=22
2y=2
y=1
Conclusion: (4,1) or x=4, y=1

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