Solve for x: ln(x-9) + ln x= ln 22?

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2007-12-19 15:47:11 · 4 answers · asked by rjmessick59 1 in Science & Mathematics ➔ Mathematics

ln [ (x - 9) (x) ] = ln 22
x ² - 9x = 22
x ² - 9x - 22 = 0
(x - 11) (x + 2) = 0
x = 11 , x = - 2
Accept + ve value of x = 11

2007-12-19 20:57:52 · answer #1 · answered by Como 7 · 2⤊ 0⤋

when you add ln's you multiply the numbers with them. So ln(x-9) + ln(x)= ln(x^2 - 9x)

that means that x^2 - 9x = 22
(x + 2)(x - 11)=0
x=-2 or 11

2007-12-19 15:57:34 · answer #2 · answered by N.S.K. 3 · 0⤊ 0⤋

ln(x-9)+lnx=ln22
ln(x-9)*x=ln22
x(x-9)=22
x2-9x-22=0
(x+2)(x-11)=0
x=-2 , 11

2007-12-19 16:05:02 · answer #3 · answered by goodi 3 · 0⤊ 0⤋

e^{ln(x-9)+lnx=ln22}
x-9+x = 22
2x=22+9
2x=31
x=31/2

2007-12-19 15:53:34 · answer #4 · answered by m_a_r_l_o2000 1 · 0⤊ 0⤋