A formula for the number of possible combinations or <em>r</em> objects from a set of <em>n</em> objects is

where n is 25 and r is 12. The number of ways is 5,200,300.
The bird will have been flying for 2 hours at 12 miles per hour. Because he is going 12 miles per hour, he will have gone 24 miles total.
Use the pythagorean theorem.
The foot of the ladder is 4 feet away from the building (leg 1)
The height of the building is leg 2
The ladder, which would be at an angle, is 12 feet. So our hypotenuse would be 12. The equation for this would be a²+4²=12²
We can then begin to solve
a² + 16 = 144
a² = 128
a=11.31
So, our answer is: The top of the ladder reaches the building at 11.31 feet up
<span> using a drawing program is easier and faster</span>
Usually, "simplify" means to remove any common factors and express the sum as a single fraction, often in multiplie-out form.
If you factor what you've got, you will write it as