Question

The speed limit is 55 minutes per hr. write an inequalit to represent the speed limit.

Answer 1

Answer: Either $x \le 55$ or $0 \le x \le 55$ depending on your teacher's preference. See the note at the bottom for more info. 

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Let x be the speed limit. It is simply a placeholder. Think of it as a box with the number inside. We don't know what the number is, but we know that the largest it can be is 55. It cannot be larger than 55.

So x can be equal to 55 or it can be smaller

Put another way, x is less than or equal to 55 which is written as $x \le 55$ (on the keyboard you would type " x <= 55 " without quotes). 

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Note: since negative speeds make no sense, we also must imply that x can't be negative. Your teacher may want you to write this in to clearly state it. If so, then you would also have $x \ge 0$ which when combined with the first inequality, you get this compound inequality $0 \le x \le 55$ (basically saying "x is some speed between 0 and 55 mph"). This very clearly states the boundaries on what x can be. Though your teacher may want you to stick to the first format as its simpler.