Solving Systems by Substitution Intro

Why might we use substitution to solve instead of solving by graphing?

• We can find fractional answers more easily

• We don't need graph paper or a graphing calculator

• One or both of the equations aren't in slope-intercept form

• We find substitution to be an easier method

Answer explanation

Any of these reasons are valid!

What does it mean to substitute?

• To guess and check

• To graph and find the intersection point

• To replace the value of a variable with an equivalent expression

• To add different variables together and see what you get

Answer explanation

Notice that when we substitute, we should no longer have two different variables (instead of y and x, we just have x)

Answer explanation

Notice that we replaced y with an equivalent expression in the correct option