3.5d + 6.25 = 1 + 5.25d

the solution is d =

d = 3

Step-by-step explanation:

3.5d + 6.25 = 1 + 5.25d

5.25d - 3.5d = 6.25 - 1

1.75d = 5.25

d = 5.25 ÷ 1.75 = 3

answer: 819.89 miles across america

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