Solve for x if \(25^{x} + 3(5^{x}) = 4\)
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Correct Answer: Option B
Explanation:
\(25^{x} + 3(5^{x}) = 4\)
Let \(5^{x}\) = y.
\((5^{2})^{x} + 3(5^{x}) - 4 = 0\)
\(y^{2} + 3y - 4 = 0\)
\(y^{2} - y + 4y - 4 = 0\)
\(y(y - 1) + 4(y - 1) = 0\)
\((y + 4)(y - 1) = 0\)
\(y = -4 ; y = 1\)
y = -4 is not possible.
y = 1 \(\implies\) x = 0.
\(25^{x} + 3(5^{x}) = 4\)
Let \(5^{x}\) = y.
\((5^{2})^{x} + 3(5^{x}) - 4 = 0\)
\(y^{2} + 3y - 4 = 0\)
\(y^{2} - y + 4y - 4 = 0\)
\(y(y - 1) + 4(y - 1) = 0\)
\((y + 4)(y - 1) = 0\)
\(y = -4 ; y = 1\)
y = -4 is not possible.
y = 1 \(\implies\) x = 0.