Practice: triangle sum theorem on a piece of paper solve for the variable , then find the missing angles can someone solve 1 2 and 3 for me please

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

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?

Suppose a gym membership has an initial enrollment fee of $75 and then a fee of $29 a month. which equation models the cost, c, of the gym membership for m months?