Question

In the following exercises, decide whether it would be more convenient to solve the system of equations by substitution or elimination.

$\left\{\begin{array}{l}y=3x-9\\ 4x-5y=23\end{array}\right.$

Short answer

It would be more convenient to solve the system of equations $\left\{\begin{array}{l}y=3x-9\\ 4x-5y=23\end{array}\right.$by the substitution method.

Step-by-step solution

Step 1. Given Information

Consider a system of equations $\left\{\begin{array}{l}y=3x-9\\ 4x-5y=23\end{array}\right.$

We need to know which method will be more convenient to solve the system of equations.

Step 2. Choosing the most convenient method 

In the given system of equations $\left\{\begin{array}{l}y=3x-9\\ 4x-5y=23\end{array}\right.$, the first equation is already solved for $y$. So it will be more convenient to use the substitution method.

We can use the first equation and substitute the value of $y$in the second equation and solve for $x$. Then using the found value we can found the corresponding $y$value.