Transcript Solving 2 step equations

Solving 2 step equations
M.Pickens©2006
Reminder
• When solving equations it is often easier to
work backwards from the order of
operations.
• For example, in 3x + 4 = 9. Order of
operations says you would multiply first
then add.
• When solving we would go backwards. We
cancel out the adding first (by subtracting),
then cancel out the multiplication (by
dividing)
M.Pickens©2006
Examples
3x + 5 = 11
-5 -5
3x = 6
3
3
x=2
-b + 7 = 5
-1b + 7 = 5
-7 -7
-1b = -2
-1
-1
b=2
We now have two things to get
away from the x, a *3 and a +5
If we leave dividing until last can
sometimes help us avoid fractions.
So first we need to subtract 5 from each side
Now we can divide both sides by 3
Remember if there is no number
in front of a variable it is an invisible 1
We now have two things to get
away from the b, a *-1 and a +7
First we need to subtract 7 from each side
Now we can divide both sides by -1
M.Pickens©2006
Examples
6 – 2v = 10
-6
-6
– 2v = 4
-2 -2
v = -2
-4 – k = 9
-4 – 1k = 9
+4
+4
– 1k = 13
-1 -1
k = -13
We now have two things to get
away from the v, a *-2 and a +6
First we need to subtract 6 from each side
Now we can divide both sides by -2
Remember if there is no number
in front of a variable it is an invisible 1
We now have two things to get
away from the k, a *-1 and a -4
First we need to add 4 to each side
Now we can divide both sides by -1
M.Pickens©2006
Examples
q
9
 12
2
+9
+9
q
 21*2
2*
2
We now have two things to get
away from the q, a /2 and a -9
First we need to add 9 to each side
Now we can multiply both sides by 2
q = 42
8 – p = 18
8 – 1p = 18
-8
-8
– 1p = 10
-1 -1
p = -10
Remember if there is no number
in front of a variable it is an invisible 1
We now have two things to get
away from the p, a *-1 and a +8
First we need to subtract 8 from each side
Now we can divide both sides by -1
M.Pickens©2006