Homework Help: Algebra

Posted by Russell on Sunday, July 18, 2010 at 7:16pm.

Atriangle has a base that is twice its height minus 4 feet. if the area is 15 square feet, find the height and base of the triangle.

Algebra - Henry, Sunday, July 18, 2010 at 7:46pm
h = x feet. B = 2X - 4.
A = Bh/2 = (2X -4)X/2 = 15.
Cross multiply:
2X^2 -4X = 30, X^2 -2X -15 = 0,
Solve for X BY FACTORING:
(X -5) (X + 3) = 0
X - 5 = 0, X = 5; X + 3 = 0, X = -3
Choose positive value: X = 5 = height.
2X -4 = 10 -4 = 6 = Base.

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