WAEC - Mathematics (2019 - No. 5)
If 7 + y = 4 (mod 8), find the least value of y, 10 \(\leq y \leq 30\)
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13
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21
คำอธิบาย
7 + y = 4 (mod 8)
y = 4 - 7 (mod 8)
y = -3 + 8 (mod 8)
y = 5 + 8 (mod 8)
y = 13
7 + y = 4 (mod 8)
y = 4 - 7 (mod 8)
y = -3 + 8 (mod 8)
y = 5 + 8 (mod 8)
y = 13