Estimate 179.35 x 0.0496, by expressing each of 179.35 and 0.0496 to one significant figure.

The first significant digit is 1. The next digit is 7, which is 5 or greater, so we round up the first significant digit.
$179.35 \approx 200$

The first non-zero digit is 4. The next digit is 9, which is 5 or greater, so we round up the first significant digit.
$0.0496 \approx 0.05$

The estimated value is $\boxed{10}$.

a) A solid cuboid measures $5 \text{cm}$ by $2 \text{cm}$ by $x \text{ cm}$. Form an expression, in terms of $x$, for the total surface area of the cuboid.

Length ($l$) $= 5 \text{ cm}$
Width ($w$) $= 2 \text{ cm}$
Height ($h$) $= x \text{ cm}$

The total surface area ($SA$) of a cuboid is given by:

The expression for the total surface area is $\boxed{20 + 14x \text{ cm}^2}$.

b) (i) The total surface area of the cuboid is $62 \text{cm}^2$. Form an equation in $x$.

The expression for the total surface area is $20 + 14x$.

The equation in $x$ is $\boxed{20 + 14x = 62}$.

b) (ii) Solve the equation in (b)(i) to find the value of $x$.

The value of $x$ is $\boxed{3}$.

9 (a) A solid object has a mass of $300 \text{kg}$ and a volume of $2 \text{m}^3$. Calculate the density of the object.

Density ($\rho$) is calculated as mass ($m$) divided by volume ($V$):

Mass ($m$) $= 300 \text{ kg}$
Volume ($V$) $= 2 \text{ m}^3$

The density of the object is $\boxed{150 \text{ kg/m}^3}$.