Question

What is the formula for the square of a sum?

a.)2a2 + ab - b2 b.)a2 + ab + 2b2

c.)a2 + 2ab + b2 d.)a2 - 2ab + b2

Answer 1

try it for yourself

(a+b) * (a+b)

this is where you have to use that FOIL thing

Answer 2

you end up with a*a + a*b + b*a + b*b

the a*b and b*a are the same thing, so when you add them they become 2ab

a*a = a^2

b*b = b^2

so you get

a^2 + 2ab + b^2