34 POINTS! 3 QUESTIONS.
I'm not good at math at all so help would be great
Thank You!

Jonathan pays $1.90 per pound for potatoes. he buys 8.3 pounds of potatoes. he determines that he will pay $15.77, before tax, for the potatoes. which best describes the reasonableness of jonathan’s solution? jonathan’s answer is reasonable because there are two decimal places in the factors and two in the product. jonathan’s answer is unreasonable because there are three decimal places in the factors and two in the product. jonathan’s answer is reasonable because is 16, and 16 is close to 15.77. jonathan’s answer is unreasonable because is 8, and 8 is not very close to 15.77.

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?