1. Solve for $x$: $$2x + 3 = 7$$ 2. Find the roots of the quadratic equation: $$x^2 - 5x + 6 = 0$$ 3. Simplify the expression: $$\frac{3x^2 - 12}{6x}$$ 4. Calculate the value of $y$ when $x = 2$ in the function: $$y = 4x^2 - 3x + 1$$ 5. Solve the system of equations: $$\begin{cases} 2x + y = 5 \\ x - y = 1 \end{cases}$$