Find the exact value of the expression 1 + cot^2(30°) - sec^2(45°)

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

He mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 x 10^23. which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?

Percent increase and decrease. original number: 45 new number: 18