ANSWER
|x – 45| = 3; minimum angle: 42
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Step-by-step explanation
In general, the distance between two real numbers x and y is given by |x - y|.
Therefore, the distance between the launch angle, x, and 45 degrees is
|x - 45|
"Within three degrees" means the maximum and minimum angles are when the distance between x and 45 is 3 degrees. We set the distance to equal 3:
|x - 45| = 3
The minimum angle can be found using subtraction. 45 less than 3 is 42 degrees, so the minimum angle is 42 degrees.
42 degrees is within 3 degrees of 45 degrees. If we added 45, that would get us the maximum angle.