The end of viking expansion in europe was due to all of the following except

- the tighter control of scandinavian monarchs over their subjects

- the civilizing force of christianity

- the inability of the vikings to penetrate the central regions of europe

- grants of land to viking settlers by the franks

The correct answer is the civilizing force of Christianity

Explanation:  The Viking era came to an end due to the growth of Christianity and how Christianity entered society, leaving not much of the Viking culture left.

he sent troops to protect the students as they entered the school.

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