Step by step
The question
Question: simplify x⁷ over x⁴.
x7x4
1 Numbers and letters apart
We split it: numbers over numbers, and each letter over the same letter.
Fractions next to each other mean times.
= x7x4
2 Cross out
We write the powers out.
x⁷ is 7 x's on top.
x⁴ is 4 x's on the bottom.
= xxxxxxxxxxx
x/x is 1.
Each x on top crosses out one x on the bottom.
4 pairs cross out.
3 x's are left on top.
The rule: same letter, divide, take away the powers.
xx = 1
7 − 4 = 3
xaxb = xa − b
So we get x³.
= x3
Let's look back.
First: numbers and letters apart.
Last: cross out.
Answer
= x3