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3 years ago

A student worked out the following problem to find

Mathematics

1 answer:

polet [3.4K]3 years ago

7 0

We have that

y=x²+3x-5
y=4x+1

using a graph tool
see the attached figure

the solution are the points
(-2,-7)
(3,13)

the solution obtained by the student
(-2,0)
(3,0)
is incorrect because the values of the coordinate y are incorrect
the values of x are correct
x1=-2
x2=3

with those values of x obtained, the student had to substitute it in any of the two equations to obtain the value of y
so
for x=3
y=4x+1------> 4*(3)+1-----> y=13

for x=-2
y=4x+1------> 4*(-2)+1-----> y=-7

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In an election, the population consists of the people who voted. Although there is overall data on how the population voted, the

andrew-mc [135]

Answer:

Answer:

P(A) = 0.39

Step-by-step explanation:

We are given;

P(W|A) = 0.7

P(W|A^c ) = 0.3

We are told that 60% of the respondents said they voted for A. Thus;

P(A|W) = 60% = 0.6

Now, using the principle of drawing lots, we can be able to find the probability of the event that they are willing to participate in the exit poll which is P(W).

Thus;

P(W) = [P(W|A) × P(A)] +[P(W∣A^c) × P(A^c)]

Now, P(A^c) can be expressed as 1 - P(A)

Thus, we now have;

P(W) = [P(W|A) × P(A)] + [P(W∣A^c) × (1 - P(A)]

Plugging in the relevant values gives;

P(W) = 0.7P(A) + 0.3(1 - P(A))

P(W) = 0.7P(A) + 0.3 - 0.3P(A)

P(W) = 0.3 + 0.4P(A)

Now,using Baye's theorem, we can find an expression for P(A|W)

Thus;

P(A|W) = [P(A ∩ W)]/P(W)

This can be further expressed as;

P(A|W) = [P(A) × P(W|A)]/P(W)

Plugging in relevant values, we have;

0.6 = 0.7P(A)/(0.3 + 0.4P(A))

Cross multiply to get;

0.6(0.3 + 0.4P(A)) = 0.7P(A)

0.18 + 0.24P(A) = 0.7P(A)

0.18 = 0.7P(A) - 0.24P(A)

0.46P(A) = 0.18

P(A) = 0.18/0.46

P(A) = 0.39

Step-by-step explanation:

braniest

4 0

3 years ago

∫<img src="https://tex.z-dn.net/?f=%5Cfrac%7Bxdx%7D%7B%28x%5E%7B2%7D%2B4%29%5E%7B3%7D%20%7D" id="TexFormula1" title="\frac{xdx}{

photoshop1234 [79]

Substitute $u=x^2+4$ and $du=2x\,dx$ . Then the integral transforms to

$\displaystyle \int \frac{x\,dx}{(x^2+4)^3} = \frac12 \int \frac{du}{u^3}$

Apply the power rule.

$\displaystyle \int \frac{du}{u^3} = -\dfrac1{2u^2} + C$

Now put the result back in terms of $x$ .

$\displaystyle \int \frac{x\,dx}{(x^2+4)^3} = \frac12 \left(-\dfrac1{2u^2} + C\right) = -\dfrac1{4u^2} + C = \boxed{-\dfrac1{4(x^2+4)^2} + C}$

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2 years ago

Solve for x, rounding to the nearest hundredth. 6•10*=1

viktelen [127]

Answer:

ur an idiot

Step-by-step explanation:

6 0

3 years ago

WILL MARK BRAINLIEST!!! PLEASE ANSWER!!! WRONG ANSWERS JUST FOR POINTS WILL BE REPORTED!!!!!!!!!!!!!!

Alchen [17]

Answer:

where's the question???

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

Can someone plz help me solved this problem I need help plz help me! Will mark you as brainiest!

I am Lyosha [343]

Answer:

13 l of 15%, 13 l of 25%, 26 l of 70%

Step-by-step explanation:

solutions:

15%, 25% and 70%

final solution:

52 l of 45%

This includes 0.45*52l= 23.4 l acid

Let's assume:

amount of 15% solution= x
amount of 25% solution= y
amount of 70% solution= z
and we have z=2y

so there are 2 equation:

x+y+z=52

0.15x+0.25y+0.7z=23.4

x+y+2y= 52 ⇒ x+3y= 52 ⇒ x= 52- 3y

0.15x+0.25y+1.4y=23.4

0.15x+1.65y=23.4
0.15*(52-3y)+1.65y=23.4
7.8-0.45y+1.65y=23.4
1.2y=23.4-7.8
1.2y= 15.6

y=15.6/1.2
y= 13 l

--------

x= 52- 3*13= 13 l
z= 2y= 2*13= 26 l

6 0

3 years ago