Since adding a constant to a function simply moved the graph upwards by that amount, solve f(x) for any value and see how much the graph given is different from that value of y...the simplest way in this case may be to simply find f(0) which is:
5*2^0=5
Clearly the graph at x=0 is at y=-2 so we can see that k is:
5+k=-2 so
k=-7
For

, we have

and so

which is, again, only valid for

.
Answer:
1 out of 6 because you have only one chance to get 4.
Step-by-step explanation:
3 + [_] ÷ 7 = 9
[_] ÷ 7 = 9 - 3
[_] = 6 x 7
[_] = 42
to check, just put 42 in the empty place and solve