PLEASE HELP
100 POINTS

A,C,F

Step-by-step explanation:

y proportional to x means y = kx

A 0*5= 0

4*5 =20

5*5 = 25  Yes

B  This is not We would have to add to get an output of 9 with an input of 0

C 0*4= 0

4*4 =16

5*4 = 20  Yes

A 0*5= 0

1*5 =5

5*5 = 25  not 1 NO

E 0*6= 0

3*6 =18

5*6 = 30 not 35  No

D 0*2= 0

2.5*2 =5

6*2 = 12  Yes

c

step-by-step explanation:

it would be see because your formula is f(x)=6x, so 6 times 1 is 6 and you go on and the best answer is c.

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