In mathematics of the second grade of junior high school, we find the real number k, so that the roots of the equation KX & # 178; + (K + 1) x + (k-1) = 0 about X are integers

In mathematics of the second grade of junior high school, we find the real number k, so that the roots of the equation KX & # 178; + (K + 1) x + (k-1) = 0 about X are integers

In the first case, k = 0, which is a linear equation of one variable, LZ should be able to solve the second Weida's theorem: X1 + x2 = - (K + 1) / K ① X1 * x2 = (k-1) / K ② ① + ②, we get X1 + x2 + x1x2 = (- 2) / kx1 + x2 + x1x2 + 1 = (- 2) / K + 1 (x1 + 1) (x2 + 1) = (- 2) / K + 1 because X1 and X2 are integers, so (- 2) / K + 1 is an integer, so k =