Which european leaders most encouraged exploration of the world.

I believe the answer is: Giovanni da Verrazano, Christopher Columbus, Henry the Navigator

Giovanni da Verrazano was known for his contribution in discovering Atlantic coast pathway of North America, Christopher Columbus was known for his contribution in discovering united states, and henry the navigator was known for his contribution in discovering western africa and atlantic ocean.

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

it would be a. that is the only one i could think of