Verified answer

PA

a1 = x - r

a2 = x

a3 = x + r

soma

3x = -15

x = -5

produto

(5 - r)*-5*(5 + r) =- 80

(5 - r)*(5 + r) = -80/-5 = 16

25 - r² = 16

r² = 9

r = 3

as raizes

x1 = x - r = -5 - 3 = -8

x2 = x = -5

x3 = x + r = -5 + 3 = -2

pronto

x1=x2-r

x2=x2

x3=x2+r

x1+x2+x3=3x2

-15=3x2

x2=- 5

x1.x2.x3=-80

(x2-r)x2(x2+r)=-80

(-5+r)-5(-5+r)-80

-5(25-r²)=-80

25-r²=16

r²=9

r=+-3

se r=-3

x1=x2-r ..=-5+3=-2

x2=x2.............= -5

x3=x2+r..= -5-3=-8

se x=3

x1=x2-r=-5-3=-8

x2=x2 .........=-5

x3=x2+r.....=-5+3=-2

Resp

-8

-5

-2

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