a+b= 12 a²-b²=72 a-b = ? answer with the full methos please?

a² - b² = 72

1) Factor as the Difference of Two Squares

( a + b )( a - b ) = 72

2) Sub in 12 for ( a + b )

12 ( a - b ) = 72

3) Divide both sides by 12 to isolate ( a - b )

a - b = 6 <-- answer

Answer:

a - b = 6

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You can find the values of a and b

   a + b = 12

+ a  - b =   6

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2a ....... = 18

a = 9 <-- answer for a

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a + b = 12

9 + b = 12

b = 3 <-- answer for b

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Answer

a = 9

b = 3

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Check

Sub the answers into one of the original equations

a² - b² = 72

9² - 3² = 72

81 - 9 = 72

72 = 72

Check

FACTOR a^2 - b^2 ... and go from there

answer - 6