Mary wants to buy a new tennis racket that cost $57.50. She has $8 and plans to save $4.50 each week. How many weeks will it take her to save the money? * 24 weeks
15 weeks
11 weeks
10 weeks

11 weeks

Step-by-step explanation:

57.5=8+4.5x

49.5=4.5x

11 = x

hey! so 1 (25) out of 4 (100) is 25 so your answer is 25%. it's like quarters!

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