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Algebra Difficulty 3.9 AMC 10/12 Find the answer South Africa

If aba \bullet b means the value of ab+a+bab + a + b, and 5x=355 \bullet x = 35, the value of xx must be

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Solution

By definition of \bullet, we know 5x=5x+5+x=6x+55 \bullet x = 5x + 5 + x = 6x + 5. If this is 3535, then 6x=306x = 30, so x=5x = 5

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