The circle below is the graph of which of the following equations

Step-by-step explanation:

we know that

The equation if the circle into center radius form is equal to

where

(h,k) is the center of the circle

r is the radius

In this problem we have

Find the radius of the circle

we know that

The distance between the center and any point that lie on the circle is equal to the radius

Let

the formula to calculate the distance between two points is equal to

substitute the values

substitute in the equation of the circle

center= (-2,0)

radius= sqrt2/2

step-by-step explanation:

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places