Question

Decide if it is more convenient to solve the system of equations using substitution or elimination.
5x-2y=-21
y=4x+9





Elimination


Substitution

Answer 1

To determine whether to use substitution or elimination, let's analyze the given system of equations:

1. \( 5x - 2y = -21 \)
2. \( y = 4x + 9 \)

**Substitution Method:**
- One of the equations is already solved for \(y\) (the second equation: \(y = 4x + 9\)).
- This makes substitution straightforward because you can directly substitute \(y\) in the first equation.

**Elimination Method:**
- For elimination, you would need to manipulate both equations in order to eliminate one of the variables. This could be done, but it requires additional steps.

**Conclusion:**
It is more convenient to solve this system using **Substitution** since one equation is already solved for \(y\), allowing for a simple substitution into the other equation.