First to answer gets brainliest and has to be correct

Which expression is equivalent to 8 (9 + x)?

jasenka [17]

Answer:

72 + 8x

you would multiply 8 by 9 + x

5 0

3 years ago

Mary is three times as old as her son. In 12 years Mary will be twice as old as her son. How old is each of them now? ANSWER QUI

BartSMP [9]

Mary is 36 and her son is 12

m=3s

m+12=2s+24

12= -s+24

s=12

3 0

2 years ago

Read 2 more answers

Help! Algebra!!!

balandron [24]

Thet contradict each other, that's why both of them are incorrect.
<span>Suppose that a polynomial has four roots: s, t, u, and v. If the polynomial were evaluated at any of these values, it would have to be zero. Therefore, the polynomial can be written in this form.

p(x)(x - s)(x - t)(x - u)(x - v), where p(x) is some non-zero polynomial

This polynomial has a degree of at least 4. It therefore cannot be cubic.

Now prove Kelsey correct. We have already proved that there can be no more than three roots. To prove that a cubic polynomial with three roots is possible, all we have to do is offer a single example of that. This one will do.

(x - 1)(x - 2)(x - 3)

This is a cubic polynomial with three roots, and four or more roots are not possible for a cubic polynomial. Kelsey is correct.

Incidentally, if this is a roller coaster we are discussing, then a cubic polynomial is not such a good idea, either for a vertical curve or a horizontal curve. I hope this helps</span><span>
</span>

4 0

3 years ago

Find the work done by F= (x^2+y)i + (y^2+x)j +(ze^z)k over the following path from (4,0,0) to (4,0,4)

babunello [35]

$\vec F(x,y,z)=(x^2+y)\,\vec\imath+(y^2+x)\,\vec\jmath+ze^z\,\vec k$

We want to find $f(x,y,z)$ such that $\nabla f=\vec F$ . This means

$\dfrac{\partial f}{\partial x}=x^2+y$

$\dfrac{\partial f}{\partial y}=y^2+x$

$\dfrac{\partial f}{\partial z}=ze^z$

Integrating both sides of the latter equation with respect to $z$ tells us

$f(x,y,z)=e^z(z-1)+g(x,y)$

and differentiating with respect to $x$ gives

$x^2+y=\dfrac{\partial g}{\partial x}$

Integrating both sides with respect to $x$ gives

$g(x,y)=\dfrac{x^3}3+xy+h(y)$

Then

$f(x,y,z)=e^z(z-1)+\dfrac{x^3}3+xy+h(y)$

and differentiating both sides with respect to $y$ gives

$y^2+x=x+\dfrac{\mathrm dh}{\mathrm dy}\implies\dfrac{\mathrm dh}{\mathrm dy}=y^2\implies h(y)=\dfrac{y^3}3+C$

So the scalar potential function is

$\boxed{f(x,y,z)=e^z(z-1)+\dfrac{x^3}3+xy+\dfrac{y^3}3+C}$

By the fundamental theorem of calculus, the work done by $\vec F$ along any path depends only on the endpoints of that path. In particular, the work done over the line segment (call it $L$ ) in part (a) is

$\displaystyle\int_L\vec F\cdot\mathrm d\vec r=f(4,0,4)-f(4,0,0)=\boxed{1+3e^4}$

and $\vec F$ does the same amount of work over both of the other paths.

In part (b), I don't know what is meant by "df/dt for F"...

In part (c), you're asked to find the work over the 2 parts (call them $L_1$ and $L_2$ ) of the given path. Using the fundamental theorem makes this trivial:

$\displaystyle\int_{L_1}\vec F\cdot\mathrm d\vec r=f(0,0,0)-f(4,0,0)=-\frac{64}3$

$\displaystyle\int_{L_2}\vec F\cdot\mathrm d\vec r=f(4,0,4)-f(0,0,0)=\frac{67}3+3e^4$

8 0

2 years ago

URGENT! PLEASE HELP.

uysha [10]

Answer: a) BC = 1386.8 ft

b) CD = 565.8 ft

Step-by-step explanation:

Looking at the triangle,

AD = BD + 7600

BD = AD - 7600

Considering triangle BCD, we would apply the the tangent trigonometric ratio.

Tan θ = opposite side/adjacent side. Therefore,

Tan 24 = CD/BD = CD/(AD - 700)

0.445 = CD/(AD - 700)

CD = 0.445(AD - 700)

CD = 0.445AD - 311.5 - - - - - - - -1

Considering triangle ADC,

Tan 16 = CD/AD

CD = ADtan16 = 0.287AD

Substituting CD = 0.287AD into equation 1, it becomes

CD = 0.445AD - 311.5

0.287AD = 0.445AD - 311.5

0.445AD - 0.287AD = 311.5

0.158AD = 311.5

AD = 311.5/0.158

AD = 1971.52

CD = 0.287AD = 0.287 × 1971.52

CD = 565.8 ft

To determine BC, we would apply the Sine trigonometric ratio which is expressed as

Sin θ = opposite side/hypotenuse

Sin 24 = CD/BC

BC = CD/Sin24 = 565.8/0.408

BC = 1386.8 ft

4 0

3 years ago