What are the three major causes of deforestation, and which is the most significant?

There are numerous causes that lead to deforestation, with some having much bigger effect than others. One of the major causes for destruction of the forests are:

- Agricultural expansion

The world population is constantly on the rise, meaning that more and more food is needed. In order to produce more food, the need for more agricultural land emerges, and in order for land to be freed for agriculture, the forests are taken down.

- Livestock ranching

The livestock ranching requires vast open grasslands. Unfortunately there isn't enough to satisfy the demand, so the forests are taken down in order to free up space for grasslands.

- Logging

The trees are used for lot of things, be it for firewood, making items, furniture, paper etc. This means that lot of trees have to be cut in order for all of those things to be possible, and the logging industry has no mercy when it comes to make profit of it.

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