What is the answer for the problem 3/4-1/3

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?

What is the circumference of a circle with an area of 50.24 cm²?

If x-1 and x+3 are the factors of x3+10x2+ax+b find a and b