Rate is an expression for a change of some unit per unit of time. For this problem, we find the rate of change of the price by a simple equation which is expressed as:
Rate = change in price / change in time Rate = ($1.20/lb - $0.90/lb) / 5 yrs - 0 Rate = $0.06 per lb per year
50-x^2=0 Move the x^2 to the other side x^2=50 Now take the square root of both sides x=+_(50)^1/2 (^1/2 means square root)(+_ is plus or minus. Sorry XD) Now simplify the square root X=+_5(2)^1/2 Voila. The answer is C
