# How do you solve #x - y = 4# and #y = x² - 34# using substitution?

##### 1 Answer

#### Answer:

Since one of the variables is already isolated in one of the equations (y; equation II), we can immediately substitute.

#### Explanation:

You can solve this by factoring. With trinomials

Substituting **both solutions** for x in the original equation we get:

Thus, the solution set is

**Practice exercises:**

- Solve the following systems by substitution. Leave answers in exact form when necessary.

a)

b)

Good luck!