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3 years ago

What is the value of the expression 12-15÷3+9 ?

1 answer:

7 0

12 - 15 ÷ 3 + 9

Following BODMAS = Bracket Order Division Multiplication Addition Subtraction

Division comes before Addition and Subtraction, so we carry out Division first.

12 - 15 ÷ 3 + 9, 15 ÷ 3 = 5

12 - 5 + 9

7 + 9

16

I hope you find this explanation useful.

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Find the value of x. Show your work.

yarga [219]

Answer:

x = 11

Step-by-step explanation:

∠BCE + ∠ECF = 180°

∴(10x + 15)° + 5x° = 180°

(15x + 15)° = 180°

15x = 180° - 15°

15x = 165°

x = 165°/15°

x = 11°

4 0

4 years ago

What is a simplified expression for 3(2x + y)

Brut [27]

Answer:

6x + 3y

Step-by-step explanation:

Multiply 3 by 2x.

Multiply 3 by y.

This is known as the distributive law.

4 0

3 years ago

Read 2 more answers

3x - 5 = 1/2x + 2x solve the equation and please show your work im confused x =___

Darya [45]

Answer:

X=2.5

Step-by-step explanation:

3x - 5 = 1/2x + 2x

3x - 1/2x - 2x = 5

1/2x = 5

X = 5 ÷ 1/2

X = 2.5

3 0

3 years ago

Find the length of side AC. A) 5/3 B) 5/2 102 D) 52 2 S.

scoray [572]

Answer:

D. 5√2/2

Step-by-step explanation:

Given triangle is right isosceles since one of the angles is 45°

Let the AC = x, then BC = x and AB is:

x² + x² = 5²
2x²=5²
x²= 5²/2
x = 5/√2
x = 5√2/2

Correct option is D

3 0

3 years ago

Evaluate the surface integral:S

rjkz [21]

Assuming $S$ does not include the plane $z=0$ , we can parameterize the region in spherical coordinates using

$\mathbf r(u,v)=\left\langle3\cos u\sin v,3\sin u\sin v,3\cos v\right\rangle$

where $0\le u\le2\pi$ and $0\le v\le\dfrac\pi/2$ . We then have

$x^2+y^2=9\cos^2u\sin^2v+9\sin^2u\sin^2v=9\sin^2v$
$(x^2+y^2)=9\sin^2v(3\cos v)=27\sin^2v\cos v$

Then the surface integral is equivalent to

$\displaystyle\iint_S(x^2+y^2)z\,\mathrm dS=27\int_{u=0}^{u=2\pi}\int_{v=0}^{v=\pi/2}\sin^2v\cos v\left\|\frac{\partial\mathbf r(u,v)}{\partial u}\times \frac{\partial\mathbf r(u,v)}{\partial u}\right\|\,\mathrm dv\,\mathrm du$

We have

$\dfrac{\partial\mathbf r(u,v)}{\partial u}=\langle-3\sin u\sin v,3\cos u\sin v,0\rangle$
$\dfrac{\partial\mathbf r(u,v)}{\partial v}=\langle3\cos u\cos v,3\sin u\cos v,-3\sin v\rangle$
$\implies\dfrac{\partial\mathbf r(u,v)}{\partial u}\times\dfrac{\partial\mathbf r(u,v)}{\partial v}=\langle-9\cos u\sin^2v,-9\sin u\sin^2v,-9\cos v\sin v\rangle$
$\implies\left\|\dfrac{\partial\mathbf r(u,v)}{\partial u}\times\dfrac{\partial\mathbf r(u,v)}{\partial v}\|=9\sin v$

So the surface integral is equivalent to

$\displaystyle243\int_{u=0}^{u=2\pi}\int_{v=0}^{v=\pi/2}\sin^3v\cos v\,\mathrm dv\,\mathrm du$
$=\displaystyle486\pi\int_{v=0}^{v=\pi/2}\sin^3v\cos v\,\mathrm dv$
$=\displaystyle486\pi\int_{w=0}^{w=1}w^3\,\mathrm dw$

where $w=\sin v\implies\mathrm dw=\cos v\,\mathrm dv$ .

$=\dfrac{243}2\pi w^4\bigg|_{w=0}^{w=1}$
$=\dfrac{243}2\pi$

4 0

3 years ago