Question

What are simple equations?

Answer 1

Let us say you have 15 apples and you want to make it 20 apples. How many more apples do you need?
Let's represent this in algebraic form.
15 + x = 20. What is x ? x = 20 -15 = 5.
(transfer 15 from left side to right side and change its sign. +15 becomes -15)
This is a simple equation.
Another example:
You go to the market to buy pens.Each pen costs Rs 4 and you have Rs 12. How many pens can you buy?
How is it written algebraically?
4x = 12 $\to x=\frac{12}{4}=3$.
(Here divide both sides by 4, $\frac{4x}{4}=x$ and $\frac{12}{4}$ becomes 3. Hence, x = 3.)