Which equation and variable would be easiest to solve for in order to solve the system by substitution? y + x = 3 5x + 3y = - 1

Use y + x = 3 and solve for either x or y.

Step-by-step explanation:

Substitution is a method to solve a system of equations by substituting an expression from one equation into the other.

To begin, first solve one equation by isolating for one variable. Choose the equation which will have the least number of steps to do so.

y + x = 3 can be solve for x or y by subtracting the other variable. Since this only requires one step use this equation. Either variable can be used.