a² - b² = 24
3a + 3b = 6
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a - b = ?
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1) a² - b² = ( a - b)( a + b)
( a - b )( a + b) = 24
2) 3a + 3b = 6
3( a + b) = 6
a + b = 6 / 3
a + b = 2
3) ( a - b)( a + b) = 24 , inlocuim a + b = 2
( a - b) · 2 = 24
a - b = 24 : 2
a - b = 12