In order for kevin to prove the polynomial identity (a+b)2=a2+2ab+b2, what is the first step that kevin needs to use to rewrite (a+b)2?
a
2(a+b)

b
a2+b2

c
(a+b)(a+b)

d
(a+b)2(a+b)2

Anyone know? is appreciated! will mark brainliest if correct!

High schoolmathematics 5 points keith is the leading goal scorer for a team in an ice hockey league. last season, he scored 42 goals in 82 games. assuming he scores goals at a constant rate, what is the slope of the line that represents this relationship if the number of games is along the x-axis and the number of goals is along the y-axis?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.