5+15x=5 () I'm not writing 20 characters

(1 + 3x).

Step-by-step explanation:

We have to evaluate the missing term within the brackets in the following equation.

The equation is, 5 + 15x = 5 (?)

Now, 5 + 15x

= 5 * 1 + 5 * 3x {We have to factorize the term where 5 is a factor}

= 5 (1 + 3x) {This is reverse of the distributive property of multiplication}

Therefore, the missing term within the brackets is (1 + 3x). (Answer)