help please!?

[flew62999]

25=1/2(3x-5)(x)

50=3x^2-5x

3x^2 - 5x -50 = 0

is this correct? and it this factorable?

 

[flew62999]

this was the problem:
The base of a triangular sign is 5ft less than 3 times the height. Find the base and height if the area of the triangle is 25 square feet.

the equation I came up with was:
25=1/2(3x-5)(x)

 

[tkhunny]

First, you need to WRITE your definitions. Mind definitions don't exist. Write them down. You have, I think, x = height of triangular sign.

Second, have you met the "Quadratic Formula"? It will just tell you the solutions.

Third, have you met the "Descriminant"? It is part of the quadratic formula and it will tell you if it can be factored. (-5)² - 4*(3)*(-50) = 25 + 600 = 625 = 25². That tells me that it can be factored.

 

[ctelady]

3x^2 - 5x -50 = 0

un-FOIL it to factor -->

(3x )(x )
The Lasts multiply to equal 50 Facors of 50 = 5*10 or 2*25 or 50*1
The only pair close enough to generate a difference of 5 (middle term results from combining the Inners and Outers). Juggle the parts so that the Inners and Outers combine to equal -5x -->

(3x +10 )(x -5 )