Identify the roots f (x) = 3x^2-27

Question

Judith Barry

Mathematics

10 February, 16:46

Identify the roots f (x) = 3x^2-27

+4

Answers (2)

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Malcolm Lam · Answer 1

Factour ouf 3

f (x) = 3 (x²-9)

recognize diference of 2 perfect squres

a²-b² = (a+b) (a-b)

x²-9=x²-3² = (x+3) (x-3)

so

f (x) = 3 (x+3) (x-3)

seto to zero to find roots

0=3 (x+3) (x-3)

0=x+3

-3=x

0=x-3

3=x

roots at x=-3 and 3

Benny · Answer 2

The answer is x=3, - 3