4) Discutere e risolvere il seguente sistema lineare al variare del parametro \( k \in \mathbb{R} \) : \[ \begin{array}{l}k x+y+z=1 \\ x+k y+z=1 \\ x+y+k z=1\end{array} \]

Evaluating functions: Linear and quadratic or cubic The functions \( f \) and \( g \) are defined as follows. \( f(x)=3 x^{3}+5 \quad g(x)=-5 x+4 \) Find \( f(-2) \) and \( g(7) \). \[ f(-2)=\square \] \( g(7)=\square \)

The cost price of a pen is Rs \( (3 x+5) \) and is selling price is \( \operatorname{Rs}(4 x+3) \) Write the formulato find protit.

/Evaluate \( :\left(\frac{4^{-8}}{8^{-4}}\right)^{3 / 4} \)

What should be, subtracted from \( 8 x-3 y+4 \) to get \( 3 x-2 y+4 \).

\( 1 \leftarrow \quad \begin{array}{r}\text { Solve the system of equations by the substitution method. } \\ \begin{aligned} x+y & =-2 \\ y & =-2 x\end{aligned}\end{array} \)