An element with mass 670 grams decays by 21.8% per minute. how much of the element is remaining after 15 minutes, to the nearest 10th of a gram?

Step-by-step explanation:

In this problem we have a exponential function of the form

where

x is the time in minutes

y is the mass of the element in grams

a is the initial value or y-intercept

b is the base

r is the rate

b=(1+r)

we have

substitute

so

For x=15 min

substitute in the exponential equation

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.

step-by-step explanation: