Answer:
36b²
Explanation:
Taking any number to the 2nd power means we're multiplying together 2 copies of that number. For example, 3² = 3 · 3 = 9. For our problem here, (6b)² = 6b · 6b. Note that 6b is just another way of writing 6 · b, so we can rewrite our expression as 6 · b · 6 · b. Since order doesn't matter in multiplication, we can swap things around so it looks like 6 · 6 · b · b. 6 · 6 = 36, and b · b can be written as b², so our solution is 36b².