Variables and One-Step Equations

What are the two basic rules for solving algebraic equations?

• Whatever you do to one side of the equal sign, you must copy and do on the other side of the equal sign

• Negative signs can be ignored

• Always start on the left side, regardless of where the variable is

• Always do the opposite operation

A number increased by 27 equals 65. What is the number?

Which equation has x = 5 as the solution?

• x + 15 = 10
• 2x = 5
• 2x = 10

Write an equation for the model above.

• x + 3 = -9
• x - 3 = 9
• 3x + 1 = 9
• 3x - 1 = 9

Larry has 57 stand arrows. He gives some to his friends, now he only has 42 left. How many arrows did he give away?

Solve for x:

• x = 20
• x = 7
• x = 10
• x = 3

Zoe bought some amount of oranges to put in her family smoothie. On the way home she dropped 17 of the oranges. When she got home, she only had 11 oranges. How many oranges did she originally buy?

To check your solution. You do what first?

• Isolate the variable

• Opposite

• Substitute the variable with the answer

• Use the "Golden Rule"

12x = 144

• x = 12
• x = 4
• x = 2
• x = 132

• 4

• b

• 3

• 11