How do you do Test 5 Section 4 #35?

The area of a rectangular garden will be its length times its width: A=lw. If we know that the length of this garden is 5 feet longer than its width, we can substitute l-5 for w: A=l(l-5). From there, we set the area equal to 104 and solve.


At this point, you can factor if that’s how you like to roll, or you can graph. To factor, simply figure out which pair of factors for 104 are 5 apart. 13 and 8 are, so you know that:


Since we’re dealing with physical lengths, we don’t need to worry about negative solutions. All we need is l=13.

To graph, simply plug the equation into your calculator. You’ll probably need to zoom out once.


In the image above, you see that the big parabola formed by y=x^2-5x-104 has a zero at x=13. That’s the value of l you’re looking for.

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