Substitution method

When solving with substitution, what is the first step?

y = 3 - x

2x - 3y = 21

Solve the system of equations using substitution

y = 4

x - 4y = 5

If two lines intersect at one point, then the system of equations has​ (a)  

Find the value of x that would result in the same value of y in both equations

(the x in the solution to the system of equations)

y = 3x

y = x + 12

Find the value of y in the system of equations

x = -2

y = 3x + 2

Combining like terms:

$$9c-4-13c+6$$

​ (a)  

What is the first step in solving with substitution?

5x + 2y = 5

y = 3x + 8

How many solutions does this system of equations have?