Simplify each expression 2x-2y-6x-3-2y+6 3x+4y+2y-4+5y-10 3x-6y-6+2x+6y+2 8x+2y+3x-9y+3x^2-2y

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Anyone know? will mark brainliest if you're correct!

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.