What is the first step to solving this system of equations using the substitution method?

Question

What is the first step to solving this system of equations using the substitution method?

x + y = 11
x = -y - 9
add the equations together
substitute -y-9 in for x in the top equation
substitute y=11 in for x in the bottom equation
No answer text provided

Answer 1

The first step to solving this system of equations using the substitution method would be to substitute the expression for x from the second equation into the first equation. This would result in a new equation with only one variable, which can then be solved.