Respuesta :
you need a number such that it = (half coefficient of x )^2
so for the first one: 1/2 * 2 = 1 , 1^2 = 1 So answer is 1
second: 1/2 * -20 = -10 , (-10)^2 = 100
third one 1/2 * 5 = 2.5 and 2.5^2 = 6.25
so for the first one: 1/2 * 2 = 1 , 1^2 = 1 So answer is 1
second: 1/2 * -20 = -10 , (-10)^2 = 100
third one 1/2 * 5 = 2.5 and 2.5^2 = 6.25