The sum of the expression 70a and 21b is equivalent to 7(10a + 3b).
An equation is an expression that is used to show the relationship between two or more variables and numbers.
Given the expression:
7(10a + 3b)
Opening the bracket:
= 70a + 21b
The sum of the expression 70a and 21b is equivalent to 7(10a + 3b).