Question

Dada la ecuación x2 – 6x – 9 = 0, si sus raíces son r y s, calcular: r2 + s2

Answer 1

x2 – 6x – 9 = 0
a = 1
b = -6
c = -9

x  = (-b +- raiz( b^2 -4(a)(c))/2(a)
x = (-(-6) +- raiz(-6^2 -4(1)(-9))/2(a)
x = +6 +- raiz(36 +36)/2
x =( +6 +- raiz (72))/2

x1 = (+6 + 8.48) /2
x1 = 14.48/2
x1= 7.24

x2 = (+6 -8.48)/2
x2= -2.48/2
x2 = -1.24

x1^2 = (7.24)^2
x1^2 = 52.41

x2^2 = (-1.24)^2
x2= 1.53