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What solution do 2x2 - 13x + 21 = 0 and 2x2 + 9x - 56 = 0 have in common? Round your answer to the nearest tenth if necessary.

 Jul 2, 2019
 #1
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If their solution is in common, we can set the equations equal to one another

So 2x^2-13x+21 = 2x^2+9x-56

-22x = -77

Solve x from here and round to the nearest tenth.

 

You are very welcome!

:P

 Jul 2, 2019
 #2
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+1

 

2x2 – 13x + 21  will factor to (2x – 7)(x – 3)

 

2x2 + 9x – 56    will factor to (2x – 7)(x + 8) 

 

The factor they have in common is (2x – 7) thus the common solution is x = 3.5  

.

 Jul 2, 2019

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