Homework Help

Solve for x and Y: 2x + 2y = 10 2x + y = 7

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Mizdee | Student, Undergraduate | (Level 1) Valedictorian

Posted May 12, 2013 at 6:58 PM via web

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Solve for x and Y:

2x + 2y = 10

2x + y = 7

2 Answers | Add Yours

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crmhaske | College Teacher | (Level 3) Associate Educator

Posted May 13, 2013 at 2:58 AM (Answer #1)

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You can use the substitution or elimination method to solve this problem.  I will show you how to use both.

Elimination method: subtract one equation from the other in order to eliminate one variable:

  2x + 2y = 10
- 2x +   y = 7
----------------
   0x + y = 3

Therefore, y = 3

Solve for x:

2x+3=7
2x=7-3
2x=4
x=2

Substitution method: rearrange one equation to create an expression for one variable, and substitute it into the second equation:

2x+y=7 --> y=7-2x

2x+2(7-2x)=10
2x+14-4x=10
-2x=-4
x = 2

y = 7-2(2)
y = 7-4
y=3

Therefore, x = 2 and y = 3 as solved using both methods.

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jess1999 | TA , Grade 9 | (Level 1) Valedictorian

Posted July 20, 2014 at 5:57 AM (Answer #2)

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2x + 2y = 10

2x + y = 7

To solve for " x " and " y " first subtract the top and bottom equation . By subtracting , you should get

y = 3 which is your answer for " y "

Now plug 3 into one of the equation as " y " 

2x + 3 = 7 subtract 3 on both side .

By subtracting by 3 on both sides , you should get

2x = 4 now divide both sides by 2

By dividing both sides by 2 , you should get

x = 2 which is your answer for " x "

So " x " = 2 and " y " = 3

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