Math: -x + 6 is greater than or equal to 10

Parabola Equations - Algebra

mash [69]

Answer:

$h=-\frac{1}{6}x^2+2x$

Step-by-step explanation:

The height of the tunnel is modeled by:

$h=rx^2+tx$

Where r and t are constants.

We know that the maximum height of the tunnel h is 6 meters.

And at ground level, the width is 12 meters.

And we want to determine the equation of the parabola.

First, since this is a quadratic, our maximum height h will occur at the vertex of our equation.

The vertex is given by:

$(-\frac{b}{2a}, f(-\frac{b}{2a}))$

In our case, we have the function:

$h=(r)x^2+(t)x$

Hence, a=r; b=t; and c=0.

Therefore, our vertex is:

$\Rightarrow -\frac{t}{2r}$

Thus, if we substitute this back into our equation, we should get 6 since 6 is the maximum height which is determine by the vertex. In other words:

$(6)=r(-\frac{t}{2r})^2+t(-\frac{t}{2r})$

Simplify:

$6=r(\frac{t^2}{4r^2})-\frac{t^2}{2r}$

Simplify:

$6=\frac{t^2}{4r}-\frac{t^2}{2r}$

Combine fractions:

$6=\frac{t^2}{4r}-\frac{2t^2}{4r}=\frac{-t^2}{4r}$

Multiply both sides by the denominator:

$24r=-t^2$

Let's solve for the constant r. Divide both sides by 24. Hence:

$r=-\frac{t^2}{24}$

Now, we can use our knowledge of the width.

We know that the width is 12 meters at ground level.

Hence, when h=0, the difference of our roots is 12.

So:

$0=rx^2+tx$

We can factor:

$0=x(rx+t)$

By the Zero Product Property:

$x=0\text{ or } rx+t=0$

So, the first zero is 0.

Therefore, the second zero must be 12 to ensure that our width is 12.

Let's isolate the second zero. Subtract t from both sides:

$rx=-t$

Divide both sides by r:

$x=-\frac{t}{r}$

We know that this zero must be 12. Thus:

$12=-\frac{t}{r}$

We have previously solved for r. Substitute:

$12=-\frac{t}{\frac{-t^2}{24}}$

Simplify:

$12=\frac{24}{t}$

Take the reciprocal of both sides:

$\frac{t}{24}=\frac{1}{12}$

Multiply both sides by 24. Hence, the value of t is:

$t=2$

Now, we can find r. r is given by:

$r=-\frac{t^2}{24}$

By substituting 2 for t, then, we acquire that:

$r=-\frac{(2)^2}{24}=-\frac{4}{24}=-\frac{1}{6}$

Therefore, for:

$h=rx^2+tx$

Our equation is:

$h=-\frac{1}{6}x^2+2x$

7 0

3 years ago

Please help I have 39 minutes to finish this

Ann [662]

Answer:

the answer is c I pretty sure

5 0

3 years ago

Choose 3 values for x that would make this inequality true x-4<20

Lyrx [107]

Answer:

5

10

15

Step-by-step explanation:

5 - 4 < 20

1 < 20 which is true

10 - 4 < 20

6 < 20 which is true

15 - 4 < 20

11 < 20 which is true

Hope it helped

8 0

3 years ago

The ratio of the numerator to the denominator of a fraction is 2 to 3. If both the numerator and the denominator are increased b

masha68 [24]

Answer:

The fraction is $\frac{4}{6}$

Option (B) is correct.

$3n-2d=0$ and $4n+8=3d+6$

Step-by-step explanation:

Let n denotes numerator and d denotes denominator of the fraction.

Given : The ratio of the numerator to the denominator of a fraction is 2 to 3.

That is $\frac{n}{d}=\frac{2}{3}$

Cross multiply , we get,

$3n=2d$

Or, $3n-2d=0$ ........(1)

Also, given : . If both the numerator and the denominator are increased by 2, the fraction becomes 3/4

That is $\frac{n+2}{d+2}=\frac{3}{4}$

Cross multiply , We get,

$4{n+2}={3}{d+2}$

$4n+8=3d+6$ .........(2)

$3d-4n=2$ .......(3)

Thus, from (1) and (2) , option (B) follows.

Solving equation (1) and (3) to get the original fraction using elimination method,

3n - 2d = 0 ............(1)

and 3d - 4n = 2 .........(3)

Multiply equation (1) by 3 , we get ,

9n - 6d = 0 ..........(4)

Multiply equation (3) by 2 , we get ,

-8n + 6d = 4 ..........(5)

Adding (4) and (5) , we get,

9n - 6d -8n + 6d = 4 + 0

⇒ n = 4

Put n = 4 in (1), we get

3n - 2d = 0 ⇒ 3(4) - 2d = 0 ⇒ 12 -2d = 0 ⇒ 12 = 2d ⇒ d = 6

so, the numerator is 4 and the denominator is 6.

Thus, the fraction is $\frac{4}{6}$

6 0

3 years ago

I am having issues with this problem in math: 27x+33x-65x=y

Gekata [30.6K]

Answer:

Step-by-step explanation:

the answer would be -5x

6 0

3 years ago