What is the axis of symmetry of the function f(x) = –(x + 9)(x – 21)?

1 answer:

3 0

First, we have to realize that this is factored form, so we have to put this in standard quadratic form using FOIL, which is a rule mandating how we multiply the numbers here. F stands for First, which means the first number inside the parentheses for both of them, then O means the first number in the first quantity(fancy word for parentheses) multiplied by the last number of the second quantity, and so forth. When you are done, you combine like terms

anyway, you end up with x²-12x-189, but you have to inverse all numbers because of the parentheses in front, so it becomes -x²+12x+189.

Now you can find the axis of symmetry uisng the equation -b=2a (oh yeah, I forgot to mention: the standard quadratic form is a(x)²+b(x)+c already). So you do -12 / -2, which then becomes 6.

The axis of symmetry is 6

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How do you answer this?

SVEN [57.7K]

$(m^{-2})^5=m^{-2\cdot5}=m^{-10}$

$x^2+3x-10=\\
x^2+5x-2x-10=\\
x(x+5)-2(x+5)=\\
(x-2)(x+5)$

4 0

3 years ago

Read 2 more answers

e) Given the following: Let X = {1, 2, 3, 4) and a relation R on X as R= {(1,2), (2,3), (3,4)}. Find the reflexive and transitiv

Naddika [18.5K]

Answer:

The answer is $\{(1,1),(2,2),(3,3),(4,4),(1,2)(2,3)(3,4),(1,3),(1,4)\}$

Step-by-step explanation:

Remember that a reflexive relation $R\subset \mathcal{P}(X)$ , where $\mathcal{P}(X)$ is the power set of $X$ , is one which conteins the ordered pairs of the form $(a,a)$ , for $a\in X$ .

So, As the reflexive and transitive closure of $R$ (that we will denote by $\overline{R}$ ) is in particular reflexive, we must add to $R$ the elements $\{(1,1) , (2,2),(3,3),(4,4) \}$

A transitive relation $R$ is one in which if the pair $(a,b)$ and the pair $(b,c)$ are in there, then the pair $(a,c)$ must be there too.

So, to complete the relation $R$ to be reflexive and transitive we must add the pair $(1,3)$ (because $(1,2),(2,3)$ are in $R$ ), the pair $(2,4)$ , and the pair $(1,4)$ because we added the pair $(2,4)$ .