The altitude of a triangle is 5 m less than its base. The area of the triangle is 80 m^2. Find the base.

( use quadratic equation form...)
so far I got this: x^2-5x=80
the only problem is, it's a triangle, so i have to also add the 1/2 part but how do I do that?

Question

The altitude of a triangle is 5 m less than its base. The area of the triangle is 80 m^2. Find the base.

( use quadratic equation form...) 
so far I got this: x^2-5x=80
the only problem is, it's a triangle, so i have to also add the 1/2 part but how do I do that?

lgbasallote · Answer

$$\frac{x^2 - 5x}{2} = 80$$multipkly both sides by 2
$$x^2 - 5x = 160$$
that answer your question?

anonymous · Answer

ahhhhhh NICEE LOL THANKS :D

lgbasallote · Answer

it's like that because it's bh/2 
b = x
h = x - 5

anonymous · Answer

I M ALSO NOT GETTING THIS

anonymous · Answer

THANKS FOR THE HELP @lgbasallote

lgbasallote · Answer

just doing my avatar duties :D