Decide whether the equation is an identity. Explain. (An identity is true for any values of the variables.)

$$(x+y)^{3}=x^{3}+3 x^{2} y+3 x y^{2}+y^{3}$$

Simplify the expression. (Assume that no variable or denominator is zero.)

$$\frac{4 z^{3}+z}{2 z}$$

Combine items from each column in order to form logical sentences in the imperfect progressive tense.

$$\begin{matrix} \text{yo} & \text{} & \text{entrar en las tiendas}\\ \text{tú} & \text{estar} & \text{trabajar en la tienda}\\ \text{mi amiga} & \text{seguir} & \text{buscar una camisa}\\ \text{el dependiente} & \text{andar} & \text{probarse los zapatos}\\ \text{mis amigos y yo} & \text{continuar} & \text{mirarse en el espejo}\\ \text{mis abuelos} & \text{venir} & \text{esperar una decisión}\\ \text{Uds.} & \text{} & \text{leer en el café}\\ \end{matrix}$$

6

Define oxidation and reduction in terms of both change in oxidation number and electron loss or gain.

Use a horizontal format to find the sum. $\left(3 z^{2}-z+2\right)+\left(z^{2}-4\right)$

Consider only the species (at standard conditions)

$$\mathrm{Br}^{-}, \quad \mathrm{Br}_{2}, \quad \mathrm{H}^{+}, \quad \mathrm{H}_{2}, \quad \mathrm{La}^{3+}, \quad \mathrm{Ca}, \quad \mathrm{Cd}$$

in answering the following questions. Give reasons for your answers. Which is the strongest oxidizing agent?

Solve the equation. 3x - 42 = 0

Evaluate each expression.| -4| - |3|

Sketch the graph of the linear inequality. $x \leq 3$

The given pattern continues. Find the nth term of a sequence suggested by the pattern. 2, -4, 6, -8, 10, ...

Without referring back to the text. Fill in the blank or answer true or false. If the rate of decay of a radioactive substance is proportional to the amount A(t) remaining at time t, then the half-life of the substance is necessarily $T=-(\ln 2) / k$. Th e rate of decay of the substance at time t = T is one-half the rate of decay at t = 0. ______

Let $f(x)=\sin x$ and $g(x)=f\left(x-\frac{\pi}{4}\right)$. Sketch the graph of g.

Replace each $\bullet$ with < , >, or = to make a true sentence. $21 \bullet 0$

Let $f(x)=e^{x}$ and $g(x)=-f(-x)$. Graph f and g on the same coordinate plane.