Solve the system of equations by using the substitution method. \( \begin{array}{l}x+y=16 \\ x=3 y\end{array} \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. The solution is \( \square \). (Simplify your answer. Type an ordered pair.) B. There are infinitely many solutions. C. There is no solution.

Solve the inequality. Express the solution set in set-builder notation and interval notation. Graph the solution set on a real number line. \[ 5(x-6)>4(x-6)+x \]

Elsa løper ei løype som er \( 1,75 \mathrm{~km} \) kortere enn den William loper, Tariq løper \( 15,95 \mathrm{~km} \), og det er 2,43 lenger enn William. Hvor langt løper Elsa og William?

d) \( 16 \cdot 4^{15}:\left(8^{2} \cdot 4^{5}\right)=8^{x} \)

3. (*) Dado los vectores \( \vec{a}=\left(1,2 x_{1}, 3\right) \), \( \vec{b}=\left(-1,3 x_{2},-2 x_{1}\right), \vec{c}=\left(2,2,-3 x_{2}\right) \) los valores de \( x_{1} \quad y x_{2} \) para los cuales se cumple que \( 2 \vec{a}-3 \vec{b}+\vec{c}=(7,15,21) \) es respectivamente: a. \( (2,-1) \) b. \( (-1,2) \) c. \( (2,-3) \) d. \( (-3,1) \)

Solve the inequality. Express the solution set in set-builder notation and interval notation. Graph the solution set on a real number line. \( \frac{1}{2}(n-4)>n+5 \)