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posted by Sara on Sunday, January 15, 2012 at 1:19pm.

solve exponential equation. express in exact form. e^x-42e^-x= -19

multiply each term by e^x (e^x)^2 - 42 + 19e^x = 0 let y = e^x y^2 + 19y - 42 = 0 (y+21)(y-2) = 0 y = -21 or y = 2 so e^x = 2 x = ln 2 or e^x = -21, which has no solution x = ln2

thanks again

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