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3 years ago

Using the quadratic formula, what is the solution to 2x^2-5x-6=0 ?

1 answer:

4 0

$\bf \textit{quadratic formula}\\

\begin{array}{lcclll}
2x^2&-5x&-6&=0\\
\uparrow &\uparrow &\uparrow \\
a&b&c
\end{array}
\qquad \qquad 
x= \cfrac{ - {{ b}} \pm \sqrt { {{ b}}^2 -4{{ a}}{{ c}}}}{2{{ a}}}\\\\
-----------------------------\\\\
x=\cfrac{-(-5)\pm\sqrt{(-5)^2-4(2)(-6)}}{2(2)}\implies x=\cfrac{5\pm\sqrt{25+48}}{4}
\\\\\\
x=\cfrac{5\pm\sqrt{73}}{4}\implies x=
\begin{cases}
\cfrac{5+\sqrt{73}}{4}\\\\
\cfrac{5-\sqrt{73}}{4}
\end{cases}$

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Round 90998.0014483 to the nearest ten

svp [43]

Ten: 91000

tenth: 90998.00

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4 years ago

If the scale factor is 5/3 what is the width of the new rectangle?

vlada-n [284]

Answer:

If 24 is the width then the answer is 40 and if 30 is the width then the answer is 50

Step-by-step explanation:

We multiply both sides by the scale factor to find both sides of the new rectangle. 30 * 5/3 = 50 and 24 * 5/3 = 40, so the sides of the new rectangle are 50 and 40. It matters whether 24 or 30 are the length or width, but if 24 is the width then the answer is 40 and if 30 is the width then the answer is 50

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3 years ago

if tom spins the spinner 80 times work out an estimate for the number of times the spinner will land on 3 please help me

NNADVOKAT [17]

Answer:

The estimated number of times the spinner will land on 3 is 20.

Step-by-step explanation:

The complete question is:

A four-sided spinner is provided. If Tom spins the spinner 80 times then work out an estimate for the number of times the spinner will land on 3.

Solution:

Assume that the four-sided spinner is unbiased.

That is all the four outcomes are equally likely to be selected.

The probability that the spinner lands on any of the four numbers is:

P(1) = P (2) = P (3) = P (4) = 0.25

It is provided that Tom spins the spinner n = 80 times.

The spinner can land on any of the four numbers independently.

The random variable X, defined as the number of times the spinner lands on 3, follows a Binomial distribution with parameters n = 80 and p = 0.25.

The expected value of X is:

$E(X)=np$

$=80\times 0.25\\=20$

Thus, the estimated number of times the spinner will land on 3 is 20.

7 0

3 years ago

Members of a college chemistry department agree to contribute equal amounts of money to make up a scholarship fund of $280. Then

Zarrin [17]

Answer:

7 members

Step-by-step explanation:

Lets say that the department has n members. If each member contributes with an equal amount x and make a total of $280, we know that:

n*x = 280

Where each one colaborated with:

n*x/n = 280/n

Or what is the same that: (as the n on the left eliminate themselves)

x = 280/n (*)

Now the department hires 3 more members, so we now have n+3 members. And we know that the pass from contributing x to contribute $30 less, it is, x-30 (I omit the $ symbol for simplicity). So, know we have:

x-30 = 280/(n+3)

We can replace x here by the formulation of x we did in the (*) equation:

( 280/n) - 30 = 280/(n+3)

using common denominator:

( 280/n) - 30 n/n = 280/(n+3)

( 280 - 30 n)/n = 280/(n+3)

Cross multiplying the denominators:

( 280 - 30 n)*(n+3) = 280*(n)

280n - 30n^2 + 840 - 90n = 280n

Subtracting 280 n in both sides:

30n^2 + 840 - 90n = 0

Dividing both sides by 30:

-n^2 - 3n + 28 = 0

Factorizing this term (you can notice the factor immediately or solving with baskara resolution, I omit the baskara for simplicity):

-(n + 7)(n - 4) =0

So, n is equal to 4 and -7. As we are dealing with people we can not have -7 people, so we keep only n=4.

So, previous the new hiring there were 4 members, now there are 7.

The used to collaborate with 280/4 = $70, now the collaborate with 280/7=$40, and we see the collaboration decreased in $30.

7 0

3 years ago

What is the smallest positive prime factor of 2017^2019 +2019^2017

kogti [31]

Answer:

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers