3. Factorise each of the following. \( \begin{array}{ll}\text { (a) } a^{2}-9 & \text { (b) } 49 b^{2}-1 \\ \text { (c) } 36 c^{2}-25 d^{2} & \text { (d) } 4 m^{2}-121 n^{2} \\ \text { (e) } 18 u^{2}-50 v^{2} & \text { (f) } 45 x^{2}-320 y^{2}\end{array} \)

2 varies directly as the cube of \( x \) and inversely as \( y \). If \( z=237 \) when \( x=10 \) and \( y=2 \), find \( z \) if \( x=8 \) and Round your answer to two decimal places if necessary.

Determine the implied domain of the following function. Express your answer in interval notation. \[ g(x)=-3 x+2 \] \[ \]

Step 2 of 2: Find the value of \( f(a) \). \( \quad f(x)=4 x^{3}+4 x \)

\( \left. \begin{array} { l } { - x + y = 3 } \\ { y = 3 - x } \\ { y = x - 3 } \end{array} \right. \)

5. (a4-g9-13) Murod bilan llhomning pullari yig'indisi \( x \) so'm. Murod llhomga y so'm bersa, ularning pullari miqdori tenglashadi. Murodning necha so'm puli bor? \( \begin{array}{ll}\text { A) } \frac{x+3 y}{2} & \text { B) } \frac{x+y}{2} \\ \text { C) } \frac{x-y}{2} & \text { D) } \frac{x+2 y}{2}\end{array} \)