Answer:HCF= 2 LCM=2520Step-by-step explanation:First you need to find the gcf (greatest common factor).To do this, you need to list factors of 36, 40, and 126.36: 1, 36, 2, 18, 3, 12, 4, 9, 640: 1, 40, 2, 20, 4, 10126: 1, 126, 2, 63, 3, 42, 6, 21As you can see, the greatest number that these numbers have in common is 2. So the gcf is 2.Now on to the lcm (least common multiple).To do this you need to list multiples of these numbers.36: 36, 72, 108, 144, 180, 216, 252, 288, 324, 360, 396, 432, 468, 504, 540, 576, 612, 648, 684, 720, 75640: 40, 80, 120, 160, 200, 240, 280, 360, 400, 440, 480, 520, 560, 600, 640, 680, 720, 760, 800126: 126, 252, 378, 504, 630The list just keeps going but I can guarantee you, that the lcm is 2520.