Solve the system of equations.
-5x + 2y =9

x=1, y=7

Explanation:

the system is:

{-5x+2y=9

{y=7x

first, simplify the expression:

{-5x+2y=9

{-7x+y=0

then, multiply both sides of the equation by -2:

{-5x+2y=9

{14x-2y=0

then, eliminate one variable by adding the equations:

9x=9

divide both sides by 9:

x=1

substitute the value of x into the equation:

-7x+y=0

-7(1)+y=0

solve the equation:

y=7

the answer is:

(x,y)=(1,7)

The statement that reflects a negative point of view on the Columbian Exchange is B, Children, mothers, and even chiefs are no match for this unseen warrior.

Explanation:

The text summarizes the changes in these societies caused by the start of the Columbiam Exchange in the 15th century. According to it the exchanged caused the destruction of these diverse societies by an unseen warrior".

This unseen warrior is probably the many diseases brought by the Europeans to the New World. As they were unknown in these lands, New World's population didn't have in their bodies tools to defend them from these diseases. This was one of the major causes of these societies' destruction.