✔ 最佳答案
P和Q 的數值是找不到的.
要找出H.C.F. of P,Q and 42如下:
先設 P = 28m , Q = 28n
where m and n are two positive integer (正整數) and relatively prime (互質, ie HCF of m and n = 1)
用短除法求H.C.F. of P,Q and 42
P , Q , 42
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7 | 28m , 28n , 42
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2 | 4m , 4n , 6
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2m , 2n , 3 <--- 由於m, n 互質, HCF of 2m, 2n and 3 = 1, stop here.
therefore, HCF of P,Q and 42 = 7 x 2 = 14 (done!)