All categories

3 years ago

What is the most logical first step in solving the equation x^2+10x+25=11?

Mathematics

1 answer:

lord [1]3 years ago

5 0

Answer: The answer is (D). Take the square root of both sides of the equation.

Step-by-step explanation: Given that we are solving the following quadratic equation:

$x^2+10x+25=11.$

We are to select the most logical step among the given options in solving the above quadratic equation.

The correct answer is (D), because taking the square root of both the sides of the equation will directly result in the value of 'x' as follows:

$x^2+10x+25=11\\\\\Rightarrow \sqrt{x^2+10x+25}=\sqrt {11}\\\\\Rightarrow x+5=\pm\sqrt{11}\\\\\Rightarrow x=-5\pm\sqrt{11}.$

Thus, (d) is the answer.

You might be interested in

Find the inverse of the following function. Then prove they are inverses of one another.

solmaris [256]

Answer: $\dfrac{x^2+1}{2}$

Step-by-step explanation:

Given

$f(x)=\sqrt{2x-1}$

We can write it as

$\Rightarrow y=\sqrt{2x-1}$

Express x in terms of y

$\Rightarrow y^2=2x-1\\\\\Rightarrow x=\dfrac{y^2+1}{2}$

Replace y be x to get the inverse

$\Rightarrow f^{-1}(x)=\dfrac{x^2+1}{2}$

To prove, it is inverse of f(x). $f(f^{-1}(x))=x$

$\Rightarrow f(f^{-1}(x))=\sqrt{2\times \dfrac{x^2+1}{2}-1}\\\\\Rightarrow f(f^{-1}(x))=\sqrt{x^2+1-1}\\\\\Rightarrow f(f^{-1}(x))=x$

So, they are inverse of each other.

8 0

3 years ago

What is the square root of 121

Dvinal [7]

Answer:

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

Every day your friend commutes to school on the subway at 9 AM. If the subway is on time, she will stop for a $3 coffee on the w

Shtirlitz [24]

Answer:

1.02% probability of spending 0 dollars on coffee over the course of a five day week

7.68% probability of spending 3 dollars on coffee over the course of a five day week

23.04% probability of spending 6 dollars on coffee over the course of a five day week

34.56% probability of spending 9 dollars on coffee over the course of a five day week

25.92% probability of spending 12 dollars on coffee over the course of a five day week

7.78% probability of spending 12 dollars on coffee over the course of a five day week

Step-by-step explanation:

For each day, there are only two possible outcomes. Either the subway is on time, or it is not. Each day, the probability of the train being on time is independent from other days. So we use the binomial probability distribution to solve this problem.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

In this problem we have that:

The probability that the subway is delayed is 40%. 100-40 = 60% of the train being on time, so $p = 0.6$

The week has 5 days, so $n = 5$

She spends 3 dollars on coffee each day the train is on time.

Probabability that she spends 0 dollars on coffee:

This is the probability of the train being late all 5 days, so it is P(X = 0).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{5,0}.(0.6)^{0}.(0.4)^{5} = 0.0102$

1.02% probability of spending 0 dollars on coffee over the course of a five day week

Probabability that she spends 3 dollars on coffee:

This is the probability of the train being late for 4 days and on time for 1, so it is P(X = 1).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 1) = C_{5,1}.(0.6)^{1}.(0.4)^{4} = 0.0768$

7.68% probability of spending 3 dollars on coffee over the course of a five day week

Probabability that she spends 6 dollars on coffee:

This is the probability of the train being late for 3 days and on time for 2, so it is P(X = 2).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 2) = C_{5,2}.(0.6)^{2}.(0.4)^{3} = 0.2304$

23.04% probability of spending 6 dollars on coffee over the course of a five day week

Probabability that she spends 9 dollars on coffee:

This is the probability of the train being late for 2 days and on time for 3, so it is P(X = 3).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 3) = C_{5,3}.(0.6)^{3}.(0.4)^{2} = 0.3456$

34.56% probability of spending 9 dollars on coffee over the course of a five day week

Probabability that she spends 12 dollars on coffee:

This is the probability of the train being late for 1 day and on time for 4, so it is P(X = 4).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 4) = C_{5,4}.(0.6)^{4}.(0.4)^{1} = 0.2592$

25.92% probability of spending 12 dollars on coffee over the course of a five day week

Probabability that she spends 15 dollars on coffee:

Probability that the subway is on time all days of the week, so $P(X = 5)$ .

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 5) = C_{5,5}.(0.6)^{5}.(0.4)^{0} = 0.0778$

7.78% probability of spending 12 dollars on coffee over the course of a five day week

8 0

3 years ago

The rectangle below has an area of x^2-7x+10square meters and a width of x - 5 meters. What expression represents the length of

jolli1 [7]

Answer:

L = (x - 2) meters

Step-by-step explanation:

The area of the rectangle = (x² - 7x + 10) m²

The width = (x - 5) m

length = ?

Area of a rectangle = length × width

x² - 7x + 10 = L(x -5)

note L = length

divide both sides by (x-5)

(x² - 7x + 10)/(x - 5) = L

L = x² - 7x + 10 / (x -5)

Factorize x² - 7x + 10

find the numbers you can multiply to give you 10 and also add to give you -7

The numbers are -2 and -5. Therefore,

x² - 2x - 5x + 10 = 0

x(x - 2) - 5(x - 2) = 0

(x-5)(x-2) = 0

Let us go back to our division

L = x² - 7x + 10 / (x -5)

x² - 7x + 10 = (x-5)(x-2)

L = (x-5)(x-2) / (x -5)

L = (x - 2) meters

7 0

3 years ago

What is the discount rate for a $120.00 camera that is on sale for $105.00?

balu736 [363]

<span>The resent value, also called "discounted value," is the current worth of the camera. So, we know that the discounted value is $105.00.
The first price of the camera was $120.00.
This means that the price is decreased. In order to calculate the discount rate we should find out how many percent the camera was discounted. 105 from 120 is: 105/120*100=87.5
So, the discount is 100-87.5=12.5 %.
</span>

7 0

3 years ago