The main purpose of algebra is to solve problems.
Using equations to solve problems can be useful when we are given a word problem.
I think of a number and multiply it by 6. After adding 20 to the result, my answer is 2. What is the number I first thought of?
Let the number I first thought of be x
When I multiply by 6 and add 20, this becomes 6x + 20. This is equal to 2.
The equation is: 6x + 20 = 2
Solve to get:
6x = -18
x = -3
The number I first thought of is -3
We can check our answer by putting it back into the equation:
-3 × 6 = -18
-18 + 20 = 2 so it works.
Let's have a go at some questions now.