When finding G of five, we stick 5 in for the X. So G of five equals the negative square root 5 * 5 + 10. Five times five is 25 + 10 is 35. So we're going to use our calculator and type in square root 35. It wants us to round to the nearest hundredth, so we need 2 decimal places -5.92 approximately to do G of three. We're going to stick 3IN every time we see our X. So negative square root 5 * 3 + 10 five times three is 1515 + 10 is 25, and sqrt 25 is an exact answer. It's 5. SG of three is -5. To do the last part, we're going to stick -5 in every time we see our X, so we get the negative square root 5 * -5 + 10 five times -5 is -25 + 10 is -15 and we don't know the square root of a negative number as a real number. We'll study later in this chapter that the square root of a negative number is a complex number or an imaginary number.