Giải:
a) \(\left(3x^2-5\right)+3^4+6^0=5^3\)
\(\Leftrightarrow3x^2-5+3^4+6^0=5^3\)
\(\Leftrightarrow3x^2-5+81+1=125\)
\(\Leftrightarrow3x^2=125+5-81-1\)
\(\Leftrightarrow3x^2=48\)
\(\Leftrightarrow x^2=\dfrac{48}{3}=16\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-4\end{matrix}\right.\)
Vậy ...
b) \(3x+2x\left(2^3.5-3^2.4\right)+5^2=4^4\)
\(\Leftrightarrow3x+2x\left(8.5-9.4\right)+25=256\)
\(\Leftrightarrow3x+2x\left(40-36\right)+25=256\)
\(\Leftrightarrow3x+2x.4+25=256\)
\(\Leftrightarrow3x+8x+25=256\)
\(\Leftrightarrow11x+25=256\)
\(\Leftrightarrow11x=256-25=231\)
\(\Leftrightarrow x=\dfrac{231}{11}\)
\(\Leftrightarrow x=21\)
Vậy ...
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