A^2-b^2=21 a-b=3 what is the value of a+b

The answer is 7.
(a + b)(a - b) = a ^ 2 - b ^ 2
So, (a + b)(a - b) is 21.
Since (a - b) is 3, divide 21 by 3 to get 7.

Answill have their license immediately suspended for six(6) months;

The correct answer is b, social stratification is needed for a society to exist. marxist theory regarding social stratification is that due to the differing economic capacities among people in society, a natural separation occurs between those that own the means of production and those that sell their labour in the production chain.