Question

* How does writing equivalent equations help you solve a system of equations?

Answer 1

Equivalent equations are those which are redundant and can be eliminated

Answer 2

Writing equivalant equations help you solve a system of equations because you have to add/subtract both equations, i.e.:
12x-15y=42
3x+15y=42

You can take out both of the 15 as they make a zero pair.

Answer 3

You can write an equivalent equation from a selected equation in the system of equations to isolate a variable. You can then take that variable and substitute it into the other equations. Then you will have a system of equations with one less equation and one less variable and it will be simpler to solve.