The ration is 12 muffins to every 21 donuts
the difference from 40000 to the future value in 2020, namely 5 years later is simply the yield or interest amount.

60 because .7 times 60 equals 42 therefore the answer is 60
When finding zeros, the function has to equal zero. In other words, G(x) = 0.
For three multiplied parts to equal to zero, at least one has to be zero. -2 ≠ 0, but (x+1) or (x+7) can.
So you can equate each of those to zero and find out what the zeros are.
x+1=0
x=-1
x+7=0
x=-7
Thus the answer
x = -1 or -7