(3x-10) (3x-10)
Both of the 10's have to be negative because -10 x -10 = 100
and if you use foil -30 + -30 = -60
The fastest wind speed not related to tornadoes ever recorded was during the passage of Tropical Cyclone Olivia on 10 April 1996: an automatic weather station on Barrow Island, Australia, registered a maximum wind gust of 408 km/h (220 kn; 253 mph; 113 m/s).