<em>2x - 5 + 3x = 35
</em>
<em>simplify
</em>
<em>5x - 5 = 35
</em>
<em>add 5 to both sides
</em>
<em>5x - 5 + 5 = 35 + 5
</em>
<em>simplify
</em>
<em>5x = 40
</em>
<em>divide both sides by 5
</em>
<em>5x/5 = 40/5
</em>
<em>simplify
</em>
<em>x = 8
</em>
<em>
</em>
<em />
The exact formula for surface area for a rectangular prism is 2lw+2lh+2wh. Where l=length. W=width.h=height.
<span>Let each side perpendicular to the river be
"x".
Then the side parallel to the river is "2400-2x".</span>
The function would be:
<span>A(x) = x(2400-2x)
</span>
And it would be: A(x) = 2400x - 2x^2
To solve the equation:
<span>
You have a quadratic with a = -2 and b = 2400
</span>
Maximum Area happens where:
x = -b/2a
= -2400/(2*-2)
<span>= 600 ft. (width)
</span>
To find the length it will be:
<span>= 2400-2x = 2400-2*600 = 1200 (length)</span>