Question

Tìm X :

1) 4 ( 2X - 1 ) \(^2\) - 10 = 54

2) 5 . ( 3 \(^{2X-1}\) + 30 ) = 165

Answer 1

1) \(4\left(2x-1\right)^2-10=54\)

\(\Leftrightarrow4\left(2x-1\right)^2=64\)

\(\Leftrightarrow\left(2x-1\right)^2=16\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}2x-1=4\\2x-1=-4\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{5}{2}\\x=-\frac{3}{2}\end{array}\right.\)

2)\(5\left(3^{2x-1}+30\right)=165\)

\(\Leftrightarrow3^{2x-1}+30=33\)

\(\Leftrightarrow3^{2x-1}=3\)

\(\Leftrightarrow2x-1=1\)

\(\Leftrightarrow x=1\)