SOLUTION: Hi, I been trying to solve this problem but I can't find the right formula to do it. I tried A-1/2b*h but I don't get the answer right. Would you help me please? Thank you

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Hi, I been trying to solve this problem but I can't find the right formula to do it. I tried A-1/2b*h but I don't get the answer right. Would you help me please? Thank you       Log On


   



Question 814483: Hi,
I been trying to solve this problem but I can't find the right formula to do it. I tried A-1/2b*h but I don't get the answer right. Would you help me please?
Thank you
the face of the triangular concrete panel has an area of 45 square meters and its base is 3 meters longer than twice its height. find the length of its base

Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
a = (1/2)bh
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b = 2h + 3
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45 = (1/2)bh
45 = (1/2)(2h + 3)h
45 = (1/2)(2hh + 3h)
45 = hh + (3/2)h
a(h) = hh + (3/2)h - 45
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the above quadratic equation is in standard form, with a=1, b=1.5, and c=-45
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to solve the quadratic equation, plug this:
1 1.5 -45
into this: https://sooeet.com/math/quadratic-equation-solver.php
---
the roots of the quadratic are:
6
-7.5
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the negative root doesn't make sense as length, so use the positive root:
---
Answer:
h = 6 m
b = 15 m
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