Since they decided to be extremely ridiculous and deleted my answer for "not showing enough work", here I am again:
Since it says that Kiwi is 13 less than TWICE Granny's age, I divided 77 (Granny's age) by 2, which gave me 38.5
I then subtracted 13, since it says that she is thirteen less than that number, which gave me 25.5
I had originally said "20 or 20 and a half years old" because depending on your format of testing/worksheet, you may not have the option of putting halves.
Y equals thirty two divided by two to the x power
y=32/(2^x)
I don't know how to put this into the form you needed, because I don't think that is possible, but perhaps the first blank is 32 the second is 1 and the third is 2 to the power of x
Your equation is presented in by the following formula of y = mx + b
m = slope, it is the coefficient of X
y = 4/5 X - 3
m = 4/5