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3 years ago

12

Jane evaluates x2 – 3x + 5 for x = –2 below. Step 1: (–2)2 –3(–2) + 5 Step 2: = –4 + 6 + 5 Step 3: = 7 What, if any, was Jane’s

mistake?

1 answer:

Serhud [2]3 years ago

8 0

Answer:

The jane's mmistake is

$(-2)^{2}=(-2)*(-2)=4$

Step-by-step explanation:

It has to $x^{2} -3x+5\\x=-2\\(-2)^{2}-3(-3)+5\\4+6+5=15$

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Expand 5(8x - 3y) to its simplest form

Olenka [21]

Answer:

40x - 15y

Step-by-step explanation:

Multiply the brackets together

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Have a good day :)

6 0

3 years ago

Read 2 more answers

In a weightless environment, an astronaut lose about 1.5% calcium in their bodies per month. Suppose some astronauts flew to Mar

Usimov [2.4K]

Answer:

12.3 months

Step-by-step explanation:

You want the number of months (m) such that ...

1 - 17% = (1 -1.5%)^m

Taking logarithms:

log(0.83) = m·log(0.985)

m = log(0.83)/log(0.985) ≈ 12.3 . . . . months

5 0

3 years ago

The curves r1(t) = 2t, t2, t4 and r2(t) = sin t, sin 5t, 2t intersect at the origin. Find their angle of intersection, θ, correc

masya89 [10]

Answer:

Therefore the angle of intersection is $\theta =79.48^\circ$

Step-by-step explanation:

Angle at the intersection point of two carve is the angle of the tangents at that point.

Given,

$r_1(t)=(2t,t^2,t^4)$

and $r_2(t)=(sin t , sin5t, 2t)$

To find the tangent of a carve , we have to differentiate the carve.

$r'_1(t)=(2,2t,4t^3)$

The tangent at (0,0,0) is [ since the intersection point is (0,0,0)]

$r'_1(0)=(2,0,0)$ [ putting t= 0]

$|r'_1(0)|=\sqrt{2^2+0^2+0^2} =2$

Again,

$r'_2(t)=(cos t ,5 cos5t, 2)$

The tangent at (0,0,0) is

$r'_2(0)=(1 ,5, 2)$ [ putting t= 0]

$|r'_1(0)|=\sqrt{1^2+5^2+2^2} =\sqrt{30}$

If θ is angle between tangent, then

$cos \theta =\frac{r'_1(0).r'_2(0)}{|r'_1(0)|.|r'_2(0)|}$

$\Rightarrow cos \theta =\frac{(2,0,0).(1,5,2)}{2.\sqrt{30} }$

$\Rightarrow cos \theta =\frac{2}{2\sqrt{30} }$

$\Rightarrow cos \theta =\frac{1}{\sqrt{30} }$

$\Rightarrow \theta =cos^{-1}\frac{1}{\sqrt{30} }$

$\Rightarrow \theta =79.48^\circ$

Therefore the angle of intersection is $\theta =79.48^\circ$ .

8 0

3 years ago

A group of students organized a car wash to raise money for a local charity. The students charged $5.00 for each car they washed

Gala2k [10]

The students will earn $180 by washing cars for 9 hours.

In 3 hours the students will earn...

$5 x 12 = $60

5 dollars x 12 cars = 60 dollars

So in 3 hours the group of students will earn $60

In 9 hours the students will earn...

$60 x 3 = $180

Since the students will earn $60 per every 3 hours, you multiply $60 with 3 because if you divide 9 hours by 3 hours you will get 3. The answer you get by multiplying 60 by 3 is 180. Therefore the students can earn $180 from washing cars.

I hope this helps!

3 0

3 years ago

The Venn diagram shows the results of two events resulting from rolling a number cube.

gulaghasi [49]

Answer: $P(A\cap B)=\frac{1}{3}$

$P(A)=\frac{1}{3}$

$P(B)=1$

$P(A|B)=\frac{1}{3}$

Step-by-step explanation:

From the given figure it can be seen that

Total number on cube= n(S)=6

Intersection of A and B = n(A ∩ B)= 2

Therefore,

$P(A\cap B)=\frac{n(A\cap B)}{n(s)}=\frac{2}{6}=\frac{1}{3}$

Also, The number of elements in A = 2

Therefore,

$P(A)=\frac{n(A)}{n(s)}=\frac{2}{6}=\frac{1}{3}$

Similarly, The number of elements in B= 6

Therefore,

$P(B)=\frac{n(B)}{n(s)}=\frac{6}{6}=1$

The formula to find the conditional probability is given by :-

$P(A|B)=\frac{P(A\cap B)}{P(B)}\\\\\Rightarrow P(A|B)=\frac{\frac{1}{3}}{1}=\frac{1}{3}$

4 0

4 years ago

Read 2 more answers