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3 years ago

4−(3−5)=. does anyone know what this is ??

1 answer:

5 0

You have to do whatever is in the parentheses first which gets you:

4-(-2)

Two negatives equal one positive so it would be:

4+2

And 4 plus 2 is of course 6.

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Use the given information to write the equation of the parabola.

m_a_m_a [10]

Answer:

x² = -2y

Step-by-step explanation:

The focus is p away from the vertex, and so is the directrix.

To find the equation of the parabola, we must first determine if the parabola is horizontal or vertical.

Horizontal parabola [Standard form]: (y – k)² = 4p(x – h)
Vertical parabola [Standard form]: (x – h)² = 4p(y – k)

If the parabola is vertical, the directrix, and focus will have the same x value but different y value compared to the vertex (h, k). You can also tell if the directrix in in the form y = k – p, and if the focus is in the form (h, k + p).

Likewise, if the parabola is horizontal, the directrix, and focus will have the same y value but different x value compared to the vertex (h,k) . You can also tell if the directrix is in the form x = h – p, and if the focus is in the form (h + p, k).

For this problem, given that the vertex is at the origin (0,0), and that the focus is at the point (0, -½).

You can tell that the x value is the same for the vertex, and focus so this must be a vertical parabola. Because this is a vertical parabola, we can use the form mentioned as earlier (x – h)² = 4p(y – k).

If h = 0, and k = 0, the p value must be the difference between the k of the vertex, and the k of the focus: -½ - 0 → -½.

Now we can just plug in our known information to derive the equation!

h = 0, k = 0, p = -½ → (x - h)² = 4p(y - k) →

(x - 0)² = 4(-½)(y - 0) → x² = -2(y - 0) →

x² = -2y.

Also p = 1/4a, if you are wondering.

So because this is a vertical parabola, x² = -2y is generally the same as y = -1/2x² in standard quadratic form. I just like to think of the horizontal parabola as an inverse quadratic because it is like reflecting over the line y = x.

8 0

3 years ago

Read 2 more answers

Simplify the following expression: 3X(4-1) + (6+21)

Ilya [14]

Answer:

9x+27

Step-by-step explanation:

3x(4−1)+6+21

=9x+6+21

Combine Like Terms

=9x+6+21

=(9x)+(6+21)

=9x+27

3 0

3 years ago

Read 2 more answers

Solve using quadratic formula 6x^2-x=2

Nadya [2.5K]

$6x^2-x=2\implies 6x^2-1x-2=0 \\\\[-0.35em] ~\dotfill\\\\ ~~~~~~~~~~~~\textit{quadratic formula} \\\\ \stackrel{\stackrel{a}{\downarrow }}{6}x^2\stackrel{\stackrel{b}{\downarrow }}{-1}x\stackrel{\stackrel{c}{\downarrow }}{-2}=0 \qquad \qquad x= \cfrac{ - b \pm \sqrt { b^2 -4 a c}}{2 a}$

$x = \cfrac{ -(-1) \pm \sqrt { (-1)^2 -4(6)(-2)}}{2(6)}\implies x = \cfrac{1\pm\sqrt{1+48}}{12} \\\\\\ x = \cfrac{1\pm\sqrt{49}}{12}\implies x = \cfrac{1\pm 7}{12}\implies x = \begin{cases} \frac{8}{12}\to &\frac{2}{3}\\[1em] -\frac{6}{12}\to &-\frac{1}{2} \end{cases}$

7 0

3 years ago

Question 1 of 10

Naddika [18.5K]

Answer:

B. 6x2+x+7

Step-by-step explanation:

combine like terms

3x^2+3x^2= 6x^2

x

3+4=7

3 0

3 years ago

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The product of 4 and a number f decreased by 2 is 15

Debora [2.8K]

Answer: The number is: "2 " .

__________________________________________

Step-by-step explanation:

__________________________________________

Write the expression; which is an equation, as follows:

__________________________________________

" 4x − 12 = 2(-x) " ; in which "x" represents "the number for which we shall solve" .

___________________________________________

Note:

If the "number" = "x" ; the "opposite of the number" = " -x " ;

___________________________________________

Rewrite as: " 4x − 12 = -2x " ;

_____________________________________________

→ Add "12" ; & add "2x" ; to EACH SIDE of the equation:

4x − 12 + 12 + 2x = -2x + 12 + 2x ;

to get: 6x = 12 ;

____________________________________________________

Now, divide each side of the equation by "6" ;

to isolate "x" on one side of the equation; & to solve for "x" ;

____________________________________________________

6x / 6 = 12 / 6 ;

to get: x = 2 .

____________________________________________________

Answer: The number is: "2 " .

____________________________________________________

Let us check our answer, by plugging in "2" for "x" in our original equation:

_____________________________________________________

→ " 4x − 12 = 2(-x) " ;

Let us plug in "2" for "x" ; to see if the equation holds true; that is; if both side of the equation are equal; when "x = 2" ;

→ " 4(2) − 12 = ? 2(-2) ??

→ 8 − 12 = ? -4 ? ;

→ -4 = ? -4 ?? Yes!

__________________________________________________

7 0

3 years ago

Read 2 more answers