Rearrange and solve for $x$:

$-2(3x+4)+5=x-7$

Consider the system $\{\begin{array}{c}x=2y+1\\ 3x-y=8\end{array}$. Using substitution, find $y$.

Consider a real-world situation where a dietitian is dealing with a system of equations where the calories $c$ and the grams of protein $p$ are related to each other and are written as: $p=0.1c-5$ and $3p+2c=480$. Solve for the calorie target value $c$ by using the substitution method.

Use substitution to solve for: { 9x - 2y = 7 ; y = (5x + 1)/2 }. Find the value of x and show all of your work.

You have the system: { 7x - 2y = 5 ; 14x - 4y = 10 }. Explain the best first step and why substitution or elimination helps reveal the nature of the system before isolating any variable.