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Where’s the policeman? By Mr Ottewill
2 2
2
2
y x yx + = is said to represent a policeman on traffic duty. The
The curve
graph looks like the following which illustrates the road junction.
y
4
2
-4
-2
0
2
4
x
-2
-4
The question is: where is the policeman? See below for the answer.
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Division by 8 If the number's last 3 digits are 000 or if they form a 3-digit number evenly divisible by 8, then the number itself is divisible by 8. How about 56,789,000,000? Last 3 digits are 000, so it's divisible by 8. Try 786,565,120. The last 3 digits, 120, divide by 8 into 15, so yes, the whole number is divisible by 8.
Answer to ‘Where’s the policeman?’
2 2 2 y x yx + = is also true when x = 0 and y = 0, so the point (0, 0) is on the 2
graph as an isolated point – this point represents the policeman.
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