Question 153340
simplify: (5x^2-7x+2)-(8-4x) 

= 5x^2 - 7x + 2 - 8 + 4x

= 5x^2 - 3x - 6
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solve: 12/x+4 = 2+ x/x+4 

12/(x+4) = x/(x+4)

Since the denominators are the same, the numerators are equal.
x = 12
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Cheers,
Stan H.