\( \{ ( 6 , \nabla ) | - 9 < y \leq 9 \} \)

4. Indicar en cada proceso de solución si existe algún error. Justificar la respuesta. a. \( \operatorname{Lim}_{x \rightarrow 4} \frac{2-\sqrt{x}}{4-x}=\operatorname{Lim}_{x \rightarrow 4} \frac{2-\sqrt{x}}{4-x} \cdot \frac{2+\sqrt{x}}{2+\sqrt{x}} \) \( \left.=\operatorname{Lim}_{x \rightarrow 4} \frac{4-x}{(4-x)(2}+\sqrt{x}\right) \) \( =\operatorname{Lim}_{x \rightarrow 4} \frac{0}{2+\sqrt{x}}=\frac{0}{2+\sqrt{4}}=\frac{0}{2+2}=\frac{0}{4}=0 \)

Determine if \( \left[\begin{array}{rr}-5 & -4 \\ 0 & 1\end{array}\right] \) and \( \left[\begin{array}{cc}4 / 19 & 3 / 19 \\ -5 / 19 & 1 / 19\end{array}\right] \) are inverses of each other.

Without dividing, determine if 85,939 is divisible by 9 and explain how you know.

What is \( (f-g)(x) ? \) \[ \begin{array}{l}f(x)=-x^{2}+4 x \\ g(x)=3 x+3\end{array} \]

During the holiday season, Brianna sold scarves at a kiosk in a shopping mall. Embroidered floral scarves cost \( \$ 27 \) each, and sheer chevron scarves cost \( \$ 13 \). One day she sold 42 scarves. Total recelpts for the day were \( \$ 770 \). How many of each kind of scarf did she sell? Brianna sold \( \square \) embroidered floral scarves and \( \square \) sheer chevron scarves.