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9x^2 +x = 3^4 solve exponential equation

User Macedo
by
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1 Answer

2 votes

Answer:

Review both cases and pick the most appropriate answer

Explanation:

First case where it's 9(x^2):

9x^2 + x = 3^4

9x^2 + x = 81

9x^2 + x - 81 = 0

x = b±√(b²-4ac) / 2a

x = 1±√(1²-4(9)(-81)) / 2(9)

x = 1±√(1+2916) / 18

x = 1±√(2917) / 18

x = 1+√(2917) / 18

x = 1-√(2917) / 18

Second case where it's (9x)^2:

(9x)^2 + x = 3^4

(9x)^2 + x = 81

81x^2 + x = 81

81x^2 + x - 81 = 0

x = b±√(b²-4ac) / 2a

x = 1±√(1²-4(81)(-81)) / 2(81)

x = 1±√(1+26244) / 162

x = 1±√(26245) / 162

x = 1+√(26245) / 162

x = 1-√(26245) / 162

User Jon Kern
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