Factorise 7a+7b+a2+ab completely.

Sure, let's factorise the expression step by step:

Given expression: 7a + 7b + a^2 + ab

Step 1: Group the terms to make it easier to factorise.

7a + a^2 + 7b + ab

Step 2: Factor out the common factors in each group.

a(7 + a) + b(7 + a)

Step 3: Notice that (7 + a) is a common factor in both terms. Factor out (7 + a).

(7 + a)(a + b)

So, the expression 7a + 7b + a^2 + ab factorises to (7 + a)(a + b).