-24
0.5*[3 - sqrt(117)] = - 3.908327
and
0.5*[3 + sqrt(117)] = 6.908327
-29
-79
99
-28.87043 and 1.87043 (to 5 dp)
-21, 27
27
-29
-117
-27
391
-79
99
-28.87043 and 1.87043 (to 5 dp)
-117
-21, 27
-117
You should multiply the numbers, but add the exponents. For example: 92 x 27 = 189