Answer: 12 units
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Explanation:
Points Q and R have the same y coordinate of 6.
This means they're on the same horizontal level and we can form a number line through these points. Think of Q and R being on the x axis.
Going from -4 to 8 is a distance of 12 units because either
-4-8 = -12 which flips to +12 or 12
8-(-4) = 8+4 = 12
Effectively I used absolute value for the first part to go from -12 to 12. Distance cannot be negative.
Alternatively, you can count out the number of horizontal spaces from -4 to 8 and you should count out 12 units.
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If you need to use the distance formula, then this is what the steps may look like:
[tex]Q = (x_1,y_1) = (-4,6) \text{ and } R = (x_2, y_2) = (8,6)\\\\d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}\\\\d = \sqrt{(-4-8)^2 + (6-6)^2}\\\\d = \sqrt{(-12)^2 + (0)^2}\\\\d = \sqrt{144 + 0}\\\\d = \sqrt{144}\\\\d = 12\\\\[/tex]
In my opinion, the distance formula is overkill because we can simply apply subtraction or count out the number of spaces. It's up to you which you prefer you like better. Of course be sure to follow all instructions your teacher mentions.
If the two points weren't on the same horizontal level, then we would have no choice and have to use the distance formula. Or you could use the pythagorean theorem which is effectively what the distance formula is derived from.
