Need to write equations for 5, 6 & 7

7)
Read my note at the end of problem 5 in another post.
You already know this table represents an exponential function
since each y-coordinate is always the previous y-coordinate multiplied by 6.
That means b = 6, and you have
y = a(6)^x
Now we find "a". When x = 0, y = 5. That means a = 5.
The equation is

y = 5(6)^x