All categories

2 years ago

Find the value of this expression if x= -7 x^2+5/x+1

Mathematics

1 answer:

Ray Of Light [21]2 years ago

8 0

Answer:

-9

Step-by-step explanation:

Replace x with -7 in the expression:

x^2 + 5 / x + 1

-7^2 + 5 / -7 + 1

49 + 5 / -6

54/-6

simplify the fraction

9/-1 = -9

You might be interested in

A restaurant uses 33 pounds of pasta for a party of 14 people. If they are cooking pasta for a party of 5656 people, what should

Hoochie [10]

5656people(33lbs/14people)=13332 lbs

4 0

3 years ago

Some types of algae have the potential to cause damage to river ecosystems. Suppose the accompanying data on algae colony densit

Phantasy [73]

Answer:

$y=-2.95836 x +234.56159$

Step-by-step explanation:

We assume that th data is this one:

x: 50, 55, 50, 79, 44, 37, 70, 45, 49

y: 152, 48, 22, 35, 43, 171, 13, 185, 25

a) Compute the equation of the least-squares regression line. (Round your numerical values to five decimal places.)For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i =50+ 55+ 50+ 79+ 44+ 37+ 70+ 45+ 49=479$

$\sum_{i=1}^n y_i =152+ 48+ 22+ 35+ 43+ 171+ 13+ 185+ 25=694$

$\sum_{i=1}^n x^2_i =50^2 + 55^2 + 50^2 + 79^2 + 44^2 + 37^2 + 70^2 + 45^2 + 49^2=26897$

$\sum_{i=1}^n y^2_i =152^2 + 48^2 + 22^2 + 35^2 + 43^2 + 171^2 + 13^2 + 185^2 + 25^2=93226$

$\sum_{i=1}^n x_i y_i =50*152+ 55*48+ 50*22+ 79*35+ 44*43+ 37*171+ 70*13+ 45*185+ 49*25=32784$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=26897-\frac{479^2}{9}=1403.556$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=32784-\frac{479*694}{9}=-4152.22$

And the slope would be:

$m=-\frac{-4152.222}{1403.556}=-2.95836$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{479}{9}=53.222$

$\bar y= \frac{\sum y_i}{n}=\frac{694}{9}=77.111$

And we can find the intercept using this:

$b=\bar y -m \bar x=77.1111111-(-2.95836*53.22222222)=234.56159$

So the line would be given by:

$y=-2.95836 x +234.56159$

7 0

2 years ago

) [7 − 2x + 5y − (x − y)] − (5x + 3y − 7)

ale4655 [162]

Answer:

[7-2x+5y-(x-y) -[5x+3y-7]

= 7-2x+5y-x+y-5x-3y+7

=7+7-2x-x-5x+5y+y-3y

=14-8x+3y

=-8x+3y+14

Step-by-step explanation:

6 0

2 years ago

Read 2 more answers

Find the vertex of this parabola:<br> y = -2x2 + 4x - 10

amm1812

The parabola equation in its vertex form is y = a(x-h)² + k , where:
a is the same as the a coefficient in the standard form;
h is the x-coordinate of the parabola vertex; and.
k is the y-coordinate of the parabola vertex.
that’s how you find it

3 0

2 years ago

Which situation describes INDEPENDENT events

quester [9]

<span>The answer is A because the die rolled first time can in no way affect the outcome of the second roll of the die, so both the events are independent events which do not affect each other.</span>

4 0

3 years ago

Read 2 more answers