How did cultural diffusion most affect business during the medieval era? The use of standard Arabic coins made it easier to buy and sell goods.
Chinese numerals became commonly used and made trade easier.
Chinese weights became the standard and made it easier to buy and sell goods.
The use of Persian as one common language for merchants made trade easier.

A, the use of standard Arabic coins made it easier to buy and sell goods.

Explanation:

I just took the quiz and got it right.

adopted the practice of proskynesis, a persian court custom that involved bowing down and kissing the hand of others, depending on their rank.

simplify brackets

8 - 2a - 7 = a + 40

simplify 8 - 2a - 7 to -2a + 1

-2a + 1 = a + 40

add 2a to both sides

1 = a + 40 + 2a

simplify a + 40 + 2a to 3a + 40

1 = 3a + 40

subtract 40 from both sides

1 - 40 = 3a

simplify 1 - 40 o -39

-39 = 3a

divide both sides by 3

-39/3 = a

simplify 39/3 to 13

-13 = a

switch sides

a = -13