Question

z2-18=7z formula general

Answer 1

z²-7z-18=0

a=1
b=-7
c=-18

Resuelta por formula general:

Z₁=$\frac{-(-7)+ \sqrt{(-7)^{2} - 4 (1)(-18)} }{2(1)} = \frac{7+ \sqrt{49+72} }{2} = \frac{7+ \sqrt{21} }{2} = \frac{7+11}{2}= \frac{18}{2}$= 9

Z₂=$\frac{7- \sqrt{121} }{2}= \frac{7-11}{2} = \frac{-4}{2}$=-2

Solución:

Z₁=9
Z₂=-2

Espero que sirva!Saludos!