In science class, the average score on a lab report is 78 points, with all students scoring within 2.2 points of the average. If x represents a student's score, write an equation that represents the minimum and maximum scores.

|x + 2.2| = 78
|x − 2.2| = 78
|x + 78| = 2.2
|x − 78| = 2.2

This value of x is within 2.2 units of 78; which means that the distance from x to 78 is either 2.2 units or smaller. By "distance", I mean the distance on the number line.

|x-78| represents the distance from x to 78 on the number line.

A few examples

If x = 80, then |x-78| = |80-78| = |2| = 2 which shows 80 is 2 units away from 78.
If x = 75, then |x-78| = |75-78| = |-3| = 3 which shows 75 is 3 units away from 78.

I'll let you try other x values for practice.

Absolute value is used to avoid a negative result when computing the x-78 portion. Negative distance on a number line is not possible.

So because |x-78| represents how far x is from 78, and we want this distance to be 2.2 units, this leads us to the answer of |x − 78| = 2.2

In science class, the average score on a lab report is 78 points, with all students scoring within 2.2 points of the average. If x represents a student's score, write an equation that represents the minimum and maximum scores. |x + 2.2| = 78 |x − 2.2| = 78 |x + 78| = 2.2 |x − 78| = 2.2

Respuesta :

Answer: Choice D

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In science class, the average score on a lab report is 78 points, with all students scoring within 2.2 points of the average. If x represents a student's score, write an equation that represents the minimum and maximum scores.

|x + 2.2| = 78
|x − 2.2| = 78
|x + 78| = 2.2
|x − 78| = 2.2