Answer:
81
Step-by-step explanation:
Substituting the values of a and b
= (4 + 5)(4 + 5)
= 9 x 9
= 81
as (a+b)² = a²+2ab+b² [a=4;b=5]
⇒ 4²+2(4)(5)+5²
= 16 + 40 + 25
OR simply
(4+5)²
= (9)²
