Question

Determine as raízes das funções:

a) y= x²+11x+18

b) y= -x²+9

Answer 1

$a)y=x^2+11x+18 \\ \\ 0=x^2+11x+18 \\ \\ 0=(x+2).(x+9) \\ \\ x'+2=0 \\ x'=-2 \\ \\ x''+9=0 \\ x''=-9$

S = {-2, -9}



$b)y=-x^2+9 \\\\0=-x^2+9 \\ \\ x^2=9 \\ \\ x= \sqrt{9} \\ \\ x'=+\sqrt{9} \\ x'=3 \\ \\ x''=- \sqrt{9} \\ x''=-3$

S = {3, -3}