What river valley civilization was most isolated from invasion and contact with other civilizations

China was the most isolated of the River Valleys because of mountains & deserts, which made up 2/3 of China's land, and also because of water to the east. Writing that became a beautiful art form during the Shang Dynasty in China.

Explanation:

China was the most isolated of the River Valleys because of mountains & deserts, which made up 2/3 of China's land, and also because of water to the east. Writing that became a beautiful art form during the Shang Dynasty in China.

the mongolian invasion of china and central asia resulted in a disruption of the silk road as the chinese garrisons lost support from the chinese kingdoms which fell under the mongols. however, as the mongols established a formal dynasty in china, the successors of genghis khan restored the garrisons along the silk road allowing the safe travel caravans again.

answer

explanation

the given equation is

we can rewrite this as:

let

then the equation becomes:

the factors of 8 that sum up to -9 are {-1,-8}

we split the middle term with these factors to obtain,

we factor by grouping to obtain:

apply the zero product property to get:

but