Breaking the it down- simplifying
Answer:
comparing fossils with other engerys:
Most alternatives energy sources doesn't have as much pollution produce like fossil fuel does,
Fossil comes from underground or persevered by nature, when others can be made by renewable resources, such as Wind(windmills) , sun (solar), and water (those rolly things)
So... let's say, we have two numbers "a" and "b",
"a" is the smaller one, "b" is the larger one
so, their sum is 6
a + b = 6
3 times the smaller => 3 * a or 3a
now, two less than that
3a - 2
that equals the larger "b"
3a - 2 = b
solve for "a",
now, what's "b"? well, 3a - 2 = b :)