Algebra Equations

Lesson 1-7Pages 49-52

Equations

• An Equation is a sentence that contains an equals = sign.

• The equals = sign tells you that the expression on the left is equivalent to the expression (or value) on the right.

• 7 = 8 – 1• 3(4) = 12 • 17 = 13 + 2 + 2

Equations with Variables

• An equation with a variable is neither true or false until the variable is replaced with a number.

• A solution of an equation is a numerical value for the variable that makes the sentence true.

• 18 = 14 + t (write the equation)• 18 = 14 + 4 (use math logic to solve)• 18 = 18 (balance the equation) (simplify)*SOLVING AN EQUATION – Steps listed above.

Defining a variable

• When you choose a variable to represent one of the unknowns, it is called defining the variable. – Example: • The totale cost of a hamburger and a soft drink is $5.50.

If the drink costs $2.50, what is the cost of the hamburger? *(Let h = the cost in $ of the hamburger)

h + 2.50 = 5.50*(here we defined h as the variable)

Practice problems

Page 51 #6-28