Solving equations - part 2

So last lesson we looked at solving equation. We had a look at some simpler equations and how we solve these. This lesson we will look at a few more complicated example. The ideas behind what we do to solve these are still the same, however the equations themselves are more complicated, or involve more steps.

• The first example we will look at is 6 - 4x = 18

First, we want to get rid of the 6 on the left hand side of the equation. At the moment it is a positive 6. To get rid of it we want to take 6 away. This gives us:

6 - 4x - 6 = 18 - 6
-4x = 12

Now, we want to remove the -4 from the left hand side. At the moment we have -4 multiplied by x, so we want to do the opposite, so divide by -4. Doing this gives us:

-4x ÷ -4 = 12 ÷ -4
x = -3

So we have now solved this equation to get x = -3

• The next example we will look at is (x + 4) / 6 = 3

First, we want to get rid of the 6. In this equation, the 6 is being divided, so to get rid of it we want to multiply by 6. This gives us:

(x + 4)/6 x 6 = 3 x 6
x + 4 = 18

Now we want to get rid of the 4. To do this we subtract 4 from each side. this gives us:

x + 4 - 4 = 18 - 4
x = 14

• One last example for us to look at is 3(2x - 4) = 12

First we want to get rid of the 3. At the moment we have 3 multiplied by (2x - 4). To get rid of it, we want to divide by 3. This gives us:

3(2x - 4) ÷ 3 = 12 ÷ 3
2x - 4 = 4

Now we want to get rid of the 4 and we will do this by adding 4 to both sides. We then get:

2x - 4 + 4 = 4 + 4
2x = 8

Now to get rid of the 2, we divide both sides by 2. We then get:

2x ÷ 2 = 8 ÷ 2
x = 4 


You should now be able to do questions 1-5 on the worksheet on solving equations. If you feel like some extra work, have a look at questions 6, but don't worry about question 7. Try and get questions 1-5 finished by Monday, so we can move onto some new stuff. 

As always, if you have any questions feel free to comment on here, or email or chat to me in person.