Solve for one of the variables first ,, then whatever answer you receive from x or y , you then begin to plug it in to get other variable.
In the 17th and 18th centuries, the use of silver Spanish dollars extended from the Spanish territories in the Americas westwards to Asia and eastwards to Europe, forming the first worldwide currency
Neolithic, also known as the New Stone Age, was a time period roughly from 9000 BC to 5000 BC, it was the last period of the age before wood working began. The tools available were made from natural materials including bone, antler, hide, stone, wood, grasses, animal fibers, and the use of water. These tools were used by people to cut such as the hand axe, chopper, adze, and Celt.
The Copper Age is the early part of the Bronze Age. Copper came into use before 5,000 BC and bronze around 3,100 BC, although the times vary by region. Copper and bronze were used for the same types of tools as stone such as axes and chisels, but the new, less brittle, more durable material cut better. Bronze was cast into desired shapes and if damaged could be recast. A new tool developed in the copper age is the saw.
The earliest large-scale buildings for which evidence survives have been found in ancient Mesopotamia. The smaller dwellings only survive in traces of foundations, but the later civilizations built very sizable structures in the forms of palaces, temples and ziggurats and took particular care to build them out of materials that last, which has ensured that very considerable parts have remained intact. Major technical achievement is evidenced by the construction of great cities such as Uruk and Ur. The Ziggurat of Ur is an outstanding building of the period, despite major reconstruction work.
#2 :guerilla warfare was first used in ancient times by The Chinese general and strategist Sun Tzu,
#6 : Samuel Adams
