All categories

3 years ago

The sum of a number and 20 is no more than the sum of the square of the number and 9.

Mathematics

1 answer:

aniked [119]3 years ago

5 0

A is the correct answer.

break down the word problem.

You also have to recognize key words which figure into mathematical symbols.

ex. sum of a number and 20 is x+20

square of the number and 9 is (x+9)^2

please vote my answer brainliest! thanks.

You might be interested in

Find the slope of the line

Mashcka [7]

3/2 it’s three up and two to the right

6 0

2 years ago

Select all that apply.

Nata [24]

Answer: 12 girls to 27 students

5 boys to 9 students

15 boys to 12 girls

HOPE THIS HELPS

CAN U PLEASE GIVE ME BRAINLIEST

4 0

2 years ago

Read 2 more answers

Help me PLEASEEEEEEEEEEEEE

MariettaO [177]

Answer:

Step-by-step explanation:

5 0

2 years ago

Please I need help with differential equation. Thank you

Inga [223]

1. I suppose the ODE is supposed to be

$\mathrm dt\dfrac{y+y^{1/2}}{1-t}=\mathrm dy(t+1)$

Solving for $\dfrac{\mathrm dy}{\mathrm dt}$ gives

$\dfrac{\mathrm dy}{\mathrm dt}=\dfrac{y+y^{1/2}}{1-t^2}$

which is undefined when $t=\pm1$ . The interval of validity depends on what your initial value is. In this case, it's $t=-\dfrac12$ , so the largest interval on which a solution can exist is $-1\le t\le1$ .

2. Separating the variables gives

$\dfrac{\mathrm dy}{y+y^{1/2}}=\dfrac{\mathrm dt}{1-t^2}$

Integrate both sides. On the left, we have

$\displaystyle\int\frac{\mathrm dy}{y^{1/2}(y^{1/2}+1)}=2\int\frac{\mathrm dz}{z+1}$

where we substituted $z=y^{1/2}$ - or $z^2=y$ - and $2z\,\mathrm dz=\mathrm dy$ - or $\mathrm dz=\dfrac{\mathrm dy}{2y^{1/2}}$ .

$\displaystyle\int\frac{\mathrm dy}{y^{1/2}(y^{1/2}+1)}=2\ln|z+1|=2\ln(y^{1/2}+1)$

On the right, we have

$\dfrac1{1-t^2}=\dfrac12\left(\dfrac1{1-t}+\dfrac1{1+t}\right)$

$\displaystyle\int\frac{\mathrm dt}{1-t^2}=\dfrac12(\ln|1-t|+\ln|1+t|)+C=\ln(1-t^2)^{1/2}+C$

$2\ln(y^{1/2}+1)=\ln(1-t^2)^{1/2}+C$

$\ln(y^{1/2}+1)=\dfrac12\ln(1-t^2)^{1/2}+C$

$y^{1/2}+1=e^{\ln(1-t^2)^{1/4}+C}$

$y^{1/2}=C(1-t^2)^{1/4}-1$

I'll leave the solution in this form for now to make solving for $C$ easier. Given that $y\left(-\dfrac12\right)=1$ , we get

$1^{1/2}=C\left(1-\left(-\dfrac12\right)^2\right))^{1/4}-1$

$2=C\left(\dfrac54\right)^{1/4}$

$C=2\left(\dfrac45\right)^{1/4}$

and so our solution is

$\boxed{y(t)=\left(2\left(\dfrac45-\dfrac45t^2\right)^{1/4}-1\right)^2}$

3 0

2 years ago

If a plan can travel 470 miles per hour with the wind and 430 miles per hour against the wind find the speed of the wind and the

hjlf

470-390=80
80/2=40
The wind is 40 mph
What does find the speed of the wind in still air mean? The wind is not still air!

Do you mean find the speed of the wind or find the speed of the plane in still air? Try reading your post before clicking submit.
470-40=430
390+40=430
The plane in still air goes 430 mph

6 0

2 years ago

Read 2 more answers