real zeros of the function algebraically.

Question

Find all the real zeros of the function algebraically. (Enter your answers from smallest to largest.)

f(x) = x² + 6x + 9

f(x) = x⁴ + 4x³ – 21x²

Answer 1

0=x^2+6x+9 = (x+3)(x+3)

x+3=0 ---> x=-3 is a zero of multiplicity 2

0=x^4 + 4x^3 - 21x^2 =

x^2( x^2 + 4x - 21) =

x^2 ( x + 7 )( x - 3 )

x=-7 , x=0, x=3