A house was sold for $350,000 in the year 2000, it has appreciated by 4% each year. What is the house worth in the year 2020?

(a).   we substitute 7 for x to find that 7+a=sqrt(7b+c).   letting a arbitrarily equal 1, we see that sqrt(7b+c)=8, so 7b+c=64.   one possible solution to this equation is b=9 and c=1, for the equation x+1=sqrt(9x+1).

(b).   squaring the equation, we see that x^2+2x+1=9x+1.   subtracting 2x+1, we see that x^2=7x.   if x=0, 0^2=7*0, so x=0 is one solution, while otherwise, we can divide by x to see that x=7.   thus, our solutions are 7 and 0.

(c).   doing this task is tantamount to finding a different solution to 7b+c=64.   one such solution is b=8 and c=8, for the equation x+1=sqrt(8x+8).