Solving Equations Using Tables

Please view this tutorial and answer the follow-up questions on loose leaf to

turn in to your teacher.

When given an equation to solve for x…

1) Plug the side of the equation containing x into y= on the calculator

Ex) Solve -15x + 10 = -35 for x.

**Type -15x+10 into y=

When given an equation to solve for x…

2) Since you are replacing -35 for the ‘y’ variable you need to search for -35 in the ‘y’ column in your table

Ex) Solve -15x + 10 = -35 for x.

** Find -35 in the ‘y’ column in your table.

When given an equation to solve for x…

3) The value in the ‘x’ column is your answer to the problem.

Ex) Solve -15x + 10 = -35 for x.

** x = 3 is the correct answer to the problem.

When given an equation to solve for x…

4) To check your answer, substitute your answer back in for x. After you compute the left side of the equation it should equal the right side.

Ex) Check to see if x = 3 is the correct answer for -15x + 10 = -35.

-15(3) + 10 = -35-15x + 10 = -35

-45 + 10 = -35-35 = -35

When given an equation with an x2 term…

• Because of the parabola shape that a y = x2 graph makes, there are usually two answers for x that make the equation true.

• Ex) Solve x2 + 3x - 9 = 9 for x.

** Find 9 in the ‘y’ column twice.

When given an equation with an x2 term…

• Ex) Solve x2 + 3x - 9 = 9 for x.

** Find 9 in the ‘y’- column twice.

X = 3 is one answer.and X = -6 is the other answer.

When given an equation to solve for y…

• Since y is already by itself in the equation, you should just compute the other side of the equation.

• Ex) 3(-4) – 10 = y for y.

** Compute the left side of the equation to figure out what ‘y’ equals

3(-4) – 10 = y-12 – 10 = y

-22 = y

So, y = -22.

Follow-Up Questions

Answer the following questions on loose leafand hand them in to your teacher.

Follow-Up Questions

Solve the following equations for the missing variable:

1) x + 9 = 18

2) 3x – 18 = -30

3) -5x + 6 = -19

4) Y = 3(2)2 + 8

5) x2 – x + 2 = 8