Answer:
because JKML is a parallelogram
=> JK // ML
=> KJM + LMJ = 180⁰
<=> 3x + 20 + 5x - 8 = 180⁰
<=> 8x = 168
<=> x = 21
with x = 21 => L = 4.21 - 1 = 84 - 1 = 83⁰
