Solving Unknown Variable Equations

What branch of mathematics deals with equations with variables?

• Algebra

• Geometry

• Calculus

• Physics

How would you solve the equation 4x = 100?

• Divide 100 by 4

• Subtract 4 from 100

• Add 4 to 100

• Multiply 100 by 4

Solve for x: 7x + 7 = 21

• x = 7

• x = 4

• x = 3

• x = 2

Solve for k.... 31 - 3k = 10

• k = 10

• k = -10

• k = -7

• k = 7

1. Kylie and Ricardo decide to start a dog watching business for their neighborhood. 

3. Kylie thinks it would be best to charge customers $27 for a membership and then $5 per time they walk a dog. 

5. Ricardo thinks it would be best to charge $8 per dog walk. 

7. For what number of walks will their two plans cost the same amount of money?

Mathematical Equivalence

ON

Kylie and Ricardo decide to start a dog watching business for their neighborhood. Kylie thinks it would be best to charge customers $27 for a membership and then $5 per time they walk a dog. Ricardo thinks it would be best to charge $8 per dog walk. For what number of walks will their two plans cost the same amount of money?

Mathematical Equivalence

ON

Solve the equation:
-5x = 25

• x = 20

• x = -20

• x = -5

• x = 5

3(x - 2) = 18

• 6.7

• 4

• 8

• -4

• none of the above

Find the solution:
10 = 4x - 2

• x = 3

• x = 2

• x = -3

• x = -2

What is the result of solving for the variable?

• x = -12

• x = 3

• x = -3

• x = 12