Question

3) encontre a soma das raízes de: a)|x|²+2|x|-15=0. b)|x|²-20|x|+64=0. c)|x|²-10|x|+16=0.

Answer 1

a)x^2+2x-15=0
∆=(2)^2-4.1.(-15)
∆=4+60
∆=64
x=-2+ou-√64/2
x=-2+8/2. x=6/2. x=3
x=-2-8/2. x=-10/2. x=-5
soma--3-5=-2

b)x^2-20x+64=0
∆=(-20)^2-4.1.64
∆=400-256
∆=144
x=20+ou-√144/2
x=20+12/2. x=32/2. x=16
x=20-12/2. x=8/2. x=4
soma---16+4=20

c)x^2-10x+16=0
∆=(-10)^2-4.1.16
∆=100-64
∆=36
x=10+ou-√36/2
x=10+6/2. x=16/2. x=8
x=10-6/2 x=4/2. x=2
soma---8+2=10