Determine the value of \(2x - 5y\) when \(x = 4\) and \(y = 2\text{,}\) and when \(x = 2\text{,}\) and \(y = -3\text{.}\) Write your results as if-then statements.
2.
Check the presentation for errors. If you find one, circle it and describe the mistake in words.
\begin{equation*}
\begin{aligned}
2x + 4y \amp = 10 \\
4y \amp = 2x + 10 \amp \amp \text{Add $2x$ to both sides} \\
y \amp = \frac{2x + 10}{4} \amp \amp \text{Divide both sides by $4$} \\
y \amp = \frac{2x}{4} + \frac{10}{4} \amp \amp \text{Rewrite the fraction} \\
y \amp = \frac{x}{2} + \frac{5}{2} \amp \amp \text{Reduce}
\end{aligned}
\end{equation*}
3.
Solve the equation \(2x + 3y = 6\) for the variable \(y\) using a complete presentation.
4.
Solve the equation \(2x + 3y = 6\) for the variable \(x\) using a complete presentation.
Determine the value of \(x^2 + 2y^2\) when \(x = -1\) and \(y = 2\text{,}\) and when \(x = -2\) and \(y = -1\text{.}\) Write your results as if-then statements.
2.
Solve \(ax + by = c\) for using a complete presentation.
3.
Solve the equation \(3x - 2y - 4z = 24\) for the variable using a complete presentation.