A square rotated about its center by 360º maps onto itself at 4 different angles of rotation. You can reflect a square onto itself across 4 different lines of reflection.
I think it's B because it's makes the most sense
An equiangular triangle adds up to 180 so divide that by 3, which is the number of sides, and you get, 60, therefore, each side is 60<span>° angle.</span>
15-b=4b-5(5-3)
Multiply the bracket by -5
(-5)(5)=-25
(-5)(-3)=15
15-b=4b-25+15
15-b=4b-10
Move 15 to the other side
Sign changes from +15 to -15
15-15-b=4b-10-15
-b=4b-25
Move 4b to the other side.
-b-4b=4b-4b-25
-b-4b=-25
-5b=-25
divide both sides by -5
-5b/-5=-25/-5
Answer: b=5