Cos = adjacent / hypotenuse
cos B = 4/5
B = cos^-1 (4/5)
B = 36.869897....
B = 36.87° (nearest hundredth)
Angle B = 36.87°.
Associativ property
a(bc)=(ab)c
ability to move parenthaseese around

can also be written as 2i
where i = √-1

Rationalizing denominator,
Of course not.
If the line rises higher as it goes from left to right,
then its slope ( 'm' ) is positive.
If it sinks lower as it goes from left to right,
then its slope ( 'm' ) is negative.
The answer is A A number line with a closed circle on 3-