If the solution of the equations 4x + y = K + 1x + 4Y = 3 satisfies the condition 0 < x + y < 1, then the value range of K is () A. -4<k<1B. -4<k<0C. 0<k<9D. k>-4

If the solution of the equations 4x + y = K + 1x + 4Y = 3 satisfies the condition 0 < x + y < 1, then the value range of K is () A. -4<k<1B. -4<k<0C. 0<k<9D. k>-4

Method 1: (1) - (2) × 4 is obtained, - 15y = k-11, y = 11 − K15; (1) × 4 - (2) is obtained, 15x = 4K + 1, x = 4K + 115, ∵ 0 < x + y < 1, ∵ 11 − K15 + 4K + 115 > 011 − K15 + 4K + 115 < 1, the solution is, - 4 < K < 1