Question

Solve x2 + 9x + 9 = 0.

quantity of negative 9 plus or minus 3 square root of 5 all over 2

quantity of 9 plus or minus 3 square root of 5 all over 2

quantity of negative 9 plus or minus square root of 117 all over 2

quantity of 9 plus or minus square root of 117 all over 2

Answer 1

\[x^2+9x+9\]
This can be factored down to\[(x+3)(x+3)\]
Which can be expressed as\[(x+3)^2\]
Oh my god what is wrong with your teacher? Are they really that evil?
Seriously, that problem is factored so easily and they're making you do the quadratic formula for it?

Answer 2

Okay, hold on.
\[-b \pm \sqrt\frac{ b^2-4ac }{ 2a }\]
\[-9 \pm \sqrt\frac{ 81-(4)(1)(9) }{ 2 }\]
\[-9 \pm \sqrt\frac{ 81-36}{ 2 }\]
\[-9 \pm \sqrt\frac{ 45 }{ 2 }\]
\[-9 \pm \sqrt 22.5\]
\[x=-9 + \sqrt22.5\]
and
\[x=-9-\sqrt22.5\]
What is this sorcery? I've gone over the answer multiple times and it seems to be correct yet not correct because it's not one of the answers.

Answer 3

Taking off from where you went wrong. only b^2-4ac is under square root, not the whole fraction. \[-b \pm \sqrt{b^{2}-4ac} \] is numerator, 2a is denominator


\[(-9 \pm \sqrt{45})/2\]

square root of 45 simplifies to \[3 \sqrt{5}\]

for a final answer of

\[(-9 \pm 3\sqrt{5})/2\]

Answer 4

thank you so much!!!!