PLZ HELP QUICK

Select all the correct answers. What is 221,000,000,000,000,000,000 expressed in scientific notation?

2.21 × 10^21

2.21E20

2.21E21

2.21E-20

2.21 × 10^-21

2.21 × 10^-20

2.21 × 10^20

2.21E-21

2.21E20

2.21 × 10^20

Step-by-step explanation:

The decimal point has to go 20 places to the left to give the number 2.21; that means the exponent on the 10 is 20.

2.21E20

2.21 × 10^20

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.

dont know

step-by-step explanation: