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2 years ago

when asked to factor the x^2 - 100, a student gives the answer (x -10) (x-10). what is wrong with this answer?

1 answer:

3 0

$x^2-100\\\\=x^2-10^2\\\\=(x+10)(x-10)\\\\\text{The difference of two squares formula is}~ a^2 -b^2 =(a+b)(a-b),\\\\\text{So, the student did not apply it properly}$

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Sally can paint a room in 4 hours while it takes steve 5 hours to paint the same room. How long would it take them to paint the

sdas [7]

Answer:

I think it's 20/9 hours. so 2.222222... hours.

Step-by-step explanation:

8 0

2 years ago

PLEASE HELP 30 POINTS!!!!!!!!!!!!!!!!!!!!!!!

Anettt [7]

Since you know the value of "x", you can plug in the value for "x" in the equation.

[When an exponent is negative, you move it to the other side of the fraction to make the exponent positive.]

For example:

$x^{-2}$ or $\frac{x^{-2}}{1} =\frac{1}{x^2}$

$\frac{1}{y^{-3}} =\frac{y^3}{1}$ or y³

x = -2

f(x) = 9x + 7

f(-2) = 9(-2) + 7 = -18 + 7 = -11

$g(x)=5^x$

$g(-2)=5^{-2}=\frac{1}{5^2}=\frac{1}{25}$ (idk if you should have it as a decimal or a fraction)

x = -1

f(x) = 9x + 7

f(-1) = 9(-1) + 7 = -9 + 7 = -2

$g(x)=5^x$

$g(-1)=5^{-1}=\frac{1}{5}$

x = 0

f(x) = 9x + 7

f(0) = 9(0) + 7 = 7

$g(x)=5^x$

$g(0)=5^0=1$

x = 1

f(x) = 9x + 7

f(1) = 9(1) + 7 = 9 + 7 = 16

$g(x)=5^x$

$g(1)=5^1=5$

x = 2

f(x) = 9x + 7

f(2) = 9(2) + 7 = 18 + 7 = 25

$g(x)=5^x$

$g(2)=5^2=25$

You need to determine the solution of f(x) = g(x)

Since you know f(x) = 9x + 7 and $g(x)=5^x$ , you can plug in (9x + 7) for f(x), and ( $5^x$ ) into g(x)

f(x) = g(x)

$9x+7=5^x$ You can plug in each value of x into the equation

Your answer is x = 2 because when you plug in 2 for x in the equation, you get 25 = 25

5 0

3 years ago

Find the area of the shape

MAVERICK [17]

Answer:

A=42.5

Step-by-step explanation:

First you split this shape into a square and a triangle.

The area of the square is 5✖️5=25.

Then, there is a triangle left.

We do not know about the hypotenuse, but the sides are 5 and 7.

5✖️7=35/2<-- because it is a triangle. =17.5

You add both areas, and you get the total of 42.5.

Hope this helps!

3 0

3 years ago

If a coin is flipped 75 times, in how many ways could there be exactly two tails?

Dimas [21]

Answer:

2775 ways

Step-by-step explanation:

We have been given the case to choose exactly two tails when flipped 75 times means $^{75}C_2$

Since, $^nC_r$ is equal to $\frac{n!}{r!\cdot(n-r)!}$

Here n =75, r=2 substituting the values we will get

$\frac{75!}{2!(75-2)!}$

$n!=n\cdot (n-1)\cdot (n-2).....1$

After simplification we will get $\frac{75\cdot 74\cdot 73!}{2!\cdot73!}$

Cancel out the common term that is 73! we will get

after more simplification we will get $\frac{75\cdot 74\cdot}{2!}$

Finally, we will get $\frac{75\cdot 74\cdot}{2}=75\cdot37=2775$

4 0

3 years ago

Read 2 more answers

Two companies, A and B, make express delivery for small-item packages in a city. Company A charges a flat fee of RM70 per packag

bazaltina [42]

Using the normal probability distribution and the central limit theorem, it is found that:

a) There is a 0.1922 = 19.22% probability that Company B would charge more than Company A to deliver a small-item package.

b) The mean amount charged is of RM 51.5, with a standard deviation of 21.35.

In a normal distribution with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

It measures how many standard deviations the measure is from the mean.
After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.

By the Central Limit Theorem:

When a fixed constant k multiplies a variable, the mean is $k\mu$ and the standard deviation is $k\sigma$
When two normal variables are subtracted, the mean is the subtraction of the means, while the standard deviation is the square root of the sum of the variances.