Some signs in mathematics are implicit, that is, they do not need to be written.
If an expression, for instance, contains two times x, the multiply sign between 2 and x is usually not written.
The same applies, when a number is multiplied to parentheses.
The plus signs in front of a numbers are also usually omitted.
The addition of 1 and 2 is written like 1 + 2 = 3, not +1+2=+3.
Exponents can be used to simplify mathematical expressions.
The expression can be simplified by substituting the three times c with c raised to the third exponent.
And it can be even more simplified, because we do not need to write the times signs either:
If 1 is the factor of something it is usually omitted too. Instead of writing 1a, you can just write a.