(b) A swimming pool is being filled. At the deepest point, the depth of the water in the pool at any instant is \( h \mathrm{~m} \). The volume of water in the pool \( V \mathrm{~m}^{3} \) is given by \[ V(h)=20 h^{2}+40 h \] Find the rate at which the volume of water is changing with respect to the depth when th water in the pool is 0.75 m deep.

"Un biólogo marino encontró una especie de peces que viven a un profundidad de 1240 metros bajo el agua de cierto lago". 7) \( \quad \) La presión a dicha profundidad es: a) \( 11152 \mathrm{~N} / \mathrm{m}^{2} \) b) \( 12152 \mathrm{~N} / \mathrm{m}^{2} \) c) \( \quad 12152 \times 10^{3} \mathrm{~N} / \mathrm{m}^{2} \)

Resolven to divisiós \( \left.6 x^{4}-2 x^{3}+x-1\right):\left(x^{3}-2\right) \)

1. For 3 days in a row, Lesley ran \( 1 \frac{3}{4} \) miles. Lesley told her grandma, "I ran over 5 miles!" Is Lesley right? Explain how you know.

1.3 Factorise the following expressions fully: \( 1.3 .1 \quad 2 x^{2}-x-6 \) \( 1.3 .2 \quad a^{2}-2 \mathrm{ab}+b^{2}-100 c^{2} \) QUESTION 2 2.1 Solve for \( x \) : \( \quad x^{2}=-5 x \) Given: \( V=\frac{4}{3} \pi\left(\mathrm{R}^{3}-\mathrm{r}^{3}\right) \) Make \( r \) the subject of the formula.

QUESTION THREE (a) Find the \( x \)-coordinate of the point on the graph of the function \( f(x)=4 x- \) where the gradient is equal to 10 .