Download 9 - Houston ISD

9.21.11_9.22.11 LP Solving 1-Step and 2-Step Equations

*lesson objective: Use word problems to understand how to solve 1 and 2 step equations
Objectives—SWBAT:
 Use algebraic properties to solve one-step equations (A.4.A)
 Use algebraic properties to solve two-step equations (A.4.A)
 Determine if a solution to an equation is correct
1)
WARM UP: A factory hired 130 new workers during a year in which 27 workers retired and 59 left for other
reasons. If there were 498 workers at the end of the year, how many were there at the beginning of the year?
 X + 130 – 27 – 59 = 498
 X + 44 = 498
 X = 454 people
2) Grade HW 1.8: Combining Like Terms
3) Address formatting of mathematical expressions
4) Show how to use commutative and associative property for #5 from HW 1.8:
a. 23 + 8m + 4n – 5m – 27 =
[change all subtraction to adding a negative]
b. 23 + 8m +( 4n + -5m) + -27 = [commutative property of addition: a + b = b + a]
c. 23 + 8m + (-5m + 4n) + -27 = [associative property of addition: (a + b) + c = a + (b + c)]
d. 23 + (8m + -5m) + 4n + -27 = [combine like terms]
e. (23 + 3m) + 4n + -27= [commutative property of addition]
f. 3m +( 23 + 4n) + -27 = [commutative property of addition]
g. 3m + 4n + (23 + -27) = [combine like terms]
h. 3m + 4n + -4 =
i. 3m + 4n -4
EXPLORE: Tables work on the “Mystery Numbers” class work activity.
EXPLAIN: Define the variable. Then have students translate the sentences and explain their process.
 Note that students were undoing (using inverse operations) operations in opposite order for order of operations
( SADMEP)
 The addition, subtraction, multiplication, and division properties of equality basically state that what you do to one
side, you must do to the other (what’s one number you can’t divide by? 0) so just call it the golden rule
o When the coefficient is a fraction, multiply by the reciprocal (multiplicative inverse)
 Combine like terms on both sides of the equation to simplify expressions before solving
*Address Unit 1.1 mistakes/misunderstandings and allow students to work on corrections and/or start on HW 1.9: Solving 1
and 2 Step Equations
VOCABULARY
Equation (vs. expression): Two expressions that are equal
Unknown (vs. variable): The value being solved for in an equation. It is different than a variable since variables can change
in value. Unknowns have a set value that is not known.
One-Step Equations: Equations that require 1 step to find a solution.
Two-Step Equations: Equations that require 2 steps to find a solution.
Inverse (opposite) Operations: Operations that will “undo” another operation.
Equivalent Equations: Equations that have the same solution set.
Properties of Equality: Properties that can be applied to an equation that will generate equivalent equations.