Đáp án:
k) \(\left\{ \begin{array}{l}
y = 50\\
x = 75\\
z = 30
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
b)\dfrac{{{2^x}}}{{{2^{2.7}}}} = \dfrac{{{2^{3.2}}}}{{{2^{15}}}}\\
\to {2^{x - 14}} = {2^{ - 9}}\\
\to x - 14 = - 9\\
\to x = 5\\
h)\left\{ \begin{array}{l}
\dfrac{{x + y}}{7} = \dfrac{{x - y}}{3}\\
x.y = 250
\end{array} \right.\\
\to \left\{ \begin{array}{l}
3x + 3y = 7x - 7y\\
xy = 250
\end{array} \right.\\
\to \left\{ \begin{array}{l}
4x = 10y\\
xy = 250
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{5}{2}y\\
\dfrac{5}{2}y.y = 250
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{5}{2}y\\
{y^2} = 100
\end{array} \right.\\
\to \left[ \begin{array}{l}
y = 10\\
y = - 10
\end{array} \right. \to \left[ \begin{array}{l}
x = 25\\
x = - 25
\end{array} \right.\\
k)\left\{ \begin{array}{l}
x = \dfrac{3}{2}y\\
z = \dfrac{3}{5}y\\
\dfrac{3}{2}y + y - \dfrac{3}{5}y = 95
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{3}{2}y\\
z = \dfrac{3}{5}y\\
\dfrac{{19}}{{10}}y = 95
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = 50\\
x = 75\\
z = 30
\end{array} \right.
\end{array}\)
