Transcript Lesson 2-3 Multi- Step Equations

Lesson 2-3
Multi- Step Equations
OBJECTIVE: TSW SOLVE MULTI-STEP
EQUATIONS.
SEPTEMBER 21,2011
Solving Multi-Step Equations
 To solve multi-step equations, you must undo each
operation by working backwards
 Usually Opposite of PEMDAS

Most of the time you will add or subtract, before you multiply
or divide.
 Our goal is to still to get the variable ALONE.
Lets try one and see what happens…
 11x – 4 = 29
+ 4 +4
 11x
= 33
 11
11
x=3

*look at each operation in the equation, then work backwards!*
Read the problem: 11 times x minus 4.
Work backwards: add 4, then divide by 11
Try this one
 Remember read it first, then work backwards!
a7
5
Read: a plus 7 divided by 8
8
Backwards: multiply by 8, then
subtract 7
2 more like this
n 1
 15
2
x
 12   20
4
Consecutive integers
 Given the sequence: n, n + 1, n + 2, n + 3 …
 Plug in 1 for n.. What do you notice about the
sequence?
Consecutive integers
 Given the sequence: n, n+2, n+4, n+6
 Plug in 1 for n, what do you notice?
 Plug in 2 for n, what do you notice?
Consecutive Integers
Type
Words
Symbols
Examples
Consecutive
Integers
Integers that are in n, n+1, n+2….
counting order
-2, -1, 0, 1, 2…
Consecutive Odd
Integers
Odd integer
followed by the
next odd integer.
n, n+2, n+4,…
-1, 1, 3, 5,…
Consecutive Even
Integers
Even integers
followed by the
next even integer.
n, n+2, n+4,…
-2, 0, 2, 4,…
Example
 Write an equation for the following problem. Then solve the equation and
answer the problem.
 Find three consecutive odd integers with a sum of -51
 n + (n+2) + (n+4) = -51
 3n + 6 = -51
-6 -6
 3n
= -57
3
3
 n = -19

Plug that number back in:
n = -19
n+2 = -17
n+4 = -15
Your three consecutive odd integers are:
-19, -17, -15
Try this one
 Find three consecutive integers with a sum of 21
Homework
 Worksheet