Question

helpppppppp plsssssss

Answer 1

area of a square is side length^2

so calculate (4 + sqr5)^2

important: you cannot do 4^2 + sqrt(5)^2. you have to use the binomial expansion formula

(a+b)^2 = a^2 + 2ab + b^2

Answer 2

what does that mean

Answer 3

(a+b)^2 = a^2 + 2ab + b^2

notice how this formula has two terms added together (a and b) with the whole thing squared.

comparing this to your problem: (4 + sqrt(5))^2, your a value is 4 and your b value is sqrt(5). so with that in mind, what would your a^2 + 2ab + b^2 equal?

Answer 4

38.88854382

Answer 5

keep it in radical form (write it out in terms of square roots instead of converting to decimals)

Answer 6

4^2=16
and\[\sqrt{5}*\sqrt{5}=5\]
4*2sqrt5 = 8sqrt 5 i think
so the answer is \[21+8\sqrt{5}\]?

Answer 7

good, so the second choice from the left