Question 1186358
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The problem is far more easily solved informally than with formal algebra.<br>
6 times 3 is 18, and 3 is 3 less than 6; so the maximum length is 6.<br>
The minimum length is whatever value keeps the width positive; since the width is 3 less than the length, the minimum length is 3.<br>
ANSWER: The length can be any x in the interval (3,6)<br>
Note the length can't be 6, because the area has to be LESS THAN 18 square meters; and it can't be 3, because the width would be 0 and there would be no wall.<br>
If formal algebra is required....<br>
x = length
x-3 = width<br>
The area (length times width) has to be less than 18:<br>
{{{x(x-3)<18}}}
{{{x^2-3x<18}}}
{{{x^2-3x-18<0}}}
{{{(x-6)(x+3)<0}}}<br>
Algebraically, the solution is x between -3 and 6....<br>
But in the actual problem, since the width has to be positive (x-3>0 --> x>3), the real solution is that x is between 3 and 6.<br>