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2 years ago

Hehe help, sorry for asking a lot of questions :)

Mathematics

2 answers:

Travka [436]2 years ago

8 0

Answer:

400

Step-by-step explanation:

60 is 15% of 400

5%+ of 20

10%= 40

15%=60

leva [86]2 years ago

3 0

Answer:

B. 400

Step-by-step explanation:

---- *100% = 400%

Please mark me brainliest and have a nice day :)

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Help me answer this please:)

Dmitrij [34]

Answer:

A and B

Step-by-step explanation:

$\frac{7x+6}{2}\leq 3x+2 < ==multiply\ both\ sides\ by\ 2\\2(\frac{7x+6}{2}\leq 3x+2)\\\\7x+6\leq6x+4 < ==subtract\ -6x\ from\ both\ sides\ \\-6x \ \ -6x\\\\x+6\leq4 < ==subtract\ 6\ from\ both\ sides\\-6 \ \ \ -6\\\\x\leq-2 < ==answer\ should\ be\ anything\ less\ than\ or\ equal\ to\ -2$

Now, look at your answer choices, which options are less than or equal to -2?

x ≤ -2, Check your answers:

A. -3 ≤ -2?

This statement is correct (-3 is < -2)

B. -2 ≤ -2 <== our original answer

This statement is correct (-2 is = to -2)

C. -1 ≤ -2

This statement is incorrect (-1 is > -2, not ≤ -2)

D. 0 ≤ -2

This statement is incorrect (0 is > -2, not ≤ -2)

E. 1 < -2

This statement is incorrect (1 is > -2, not ≤ -2)

Therefore, the correct options are A and B

Hope this helps!

6 0

2 years ago

Is the square root of 5 times the square root of 5 rational?

jeka57 [31]

No 20.0000004 cannot be rational.

5 0

3 years ago

The product of (3 − 4i) and____is 25.

LiRa [457]

$(3-4i)(a+bi)=25\qquad\text{use FOIL method}\\\\(3)(a)+(3bi)+(-4i)(a)+(-4i)(bi)=25+0i\\\\3a+3bi-4ai-4bi^2=25+0i\\\\3a+3bi-4ai-4b(-1)=25+0i\\\\3a+3bi-4ai+4b=25+0i\\\\(3a+4b)+(3b-4a)i=25+0i\\.\qquad\qquad\qquad\qquad\Downarrow\\\\3a+4b=25\ and\ 3b-4a=0\\\\3b-4a=0\qquad\text{add 4a to both sides}\\\\3b=4a\qquad\text{divide both sides by 3}\\\\b=\dfrac{4}{3}a\qquad\text{substitute it to the first equation}\\\\3a+4\left(\dfrac{4}{3}a\right)=25\\\\3a+\dfrac{16}{3}a=25\qquad\text{multiply both sides by 3}$

$9a+16a=75\\\\25a=75\qquad\text{divide both sides by 25}\\\\\boxed{a=3}\qquad\text{put the value of a to}\ b=\dfrac{4}{3}a:\\\\b=\dfrac{4}{3}(3)\\\\\boxed{b=4}\\\\Answer:\ \boxed{(3-4i)\underline{(3+4i)}=25}$

6 0

3 years ago

The equation giving a family of ellipsoids is u = (x^2)/(a^2) + (y^2)/(b^2) + (z^2)/(c^2) . Find the unit vector normal to each

Fynjy0 [20]

Answer:

$\hat{n}\ =\ \ \dfrac{\dfrac{x}{a^2}\hat{i}+\ \dfrac{y}{b^2}\hat{j}+\ \dfrac{z}{c^2}\hat{k}}{\sqrt{(\dfrac{x}{a^2})^2+(\dfrac{y}{b^2})^2+(\dfrac{z}{c^2})^2}}$

Step-by-step explanation:

Given equation of ellipsoids,

$u\ =\ \dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}+\dfrac{z^2}{c^2}$

The vector normal to the given equation of ellipsoid will be given by

$\vec{n}\ =\textrm{gradient of u}$

$=\bigtriangledown u$

$=\ (\dfrac{\partial{}}{\partial{x}}\hat{i}+ \dfrac{\partial{}}{\partial{y}}\hat{j}+ \dfrac{\partial{}}{\partial{z}}\hat{k})(\dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}+\dfrac{z^2}{c^2})$

$=\ \dfrac{\partial{(\dfrac{x^2}{a^2})}}{\partial{x}}\hat{i}+\dfrac{\partial{(\dfrac{y^2}{b^2})}}{\partial{y}}\hat{j}+\dfrac{\partial{(\dfrac{z^2}{c^2})}}{\partial{z}}\hat{k}$

$=\ \dfrac{2x}{a^2}\hat{i}+\ \dfrac{2y}{b^2}\hat{j}+\ \dfrac{2z}{c^2}\hat{k}$

Hence, the unit normal vector can be given by,

$\hat{n}\ =\ \dfrac{\vec{n}}{\left|\vec{n}\right|}$

$=\ \dfrac{\dfrac{2x}{a^2}\hat{i}+\ \dfrac{2y}{b^2}\hat{j}+\ \dfrac{2z}{c^2}\hat{k}}{\sqrt{(\dfrac{2x}{a^2})^2+(\dfrac{2y}{b^2})^2+(\dfrac{2z}{c^2})^2}}$

$=\ \dfrac{\dfrac{x}{a^2}\hat{i}+\ \dfrac{y}{b^2}\hat{j}+\ \dfrac{z}{c^2}\hat{k}}{\sqrt{(\dfrac{x}{a^2})^2+(\dfrac{y}{b^2})^2+(\dfrac{z}{c^2})^2}}$

Hence, the unit vector normal to each point of the given ellipsoid surface is

$\hat{n}\ =\ \ \dfrac{\dfrac{x}{a^2}\hat{i}+\ \dfrac{y}{b^2}\hat{j}+\ \dfrac{z}{c^2}\hat{k}}{\sqrt{(\dfrac{x}{a^2})^2+(\dfrac{y}{b^2})^2+(\dfrac{z}{c^2})^2}}$

3 0

3 years ago

How many square centimeters are in an area of 5.60 in2?

Phantasy [73]

1 square inch = 2.54^2 = 6.4516 square cms

So 5.60 in^2 = 6.60 * 6.4516 = 36.13cm^2 to nearest hundredth

7 0

3 years ago