95基隆6.23
版主: thepiano
Re: 95基隆6.23
第 6 題
http://forum.nta.org.tw/examservice/sho ... hp?t=24796
第 23 題
題目應改成:設 a,b 為整數,......
x^2 + ax + 18 = 0 有質數根
故 x^2 + ax + 18 = 0 一定是 (x - 2)(x - 9) = 0 or (x - 3)(x - 6) = 0
a = -11 or -9
x^2 + 11x + b = 0 有質數根 2,b = -26
x^2 + 9x + b = 0 有質數根 3,b = -36
http://forum.nta.org.tw/examservice/sho ... hp?t=24796
第 23 題
題目應改成:設 a,b 為整數,......
x^2 + ax + 18 = 0 有質數根
故 x^2 + ax + 18 = 0 一定是 (x - 2)(x - 9) = 0 or (x - 3)(x - 6) = 0
a = -11 or -9
x^2 + 11x + b = 0 有質數根 2,b = -26
x^2 + 9x + b = 0 有質數根 3,b = -36