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3 years ago

Solve 4x+3y=-2 3x + 5y = 15

Mathematics

1 answer:

ivann1987 [24]3 years ago

8 0

Answer:

x=-5 y=6

Step-by-step explanation:

Multiply the first by 3 and the second by -4

Then add them. Y will be 6

Put 6 for y in the first one and youll find x=-5

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A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the followin

maks197457 [2]

Answer:

(a) $\sum x_i=56.68$ and $\sum x_i^2=197.46$

(b) The sample variance is $s^2=0.530$ and the sample standard deviation is $s=0.728$

Step-by-step explanation:

(a)

The sum of these 17 sample observations is

$\sum x_i=2.79\:+2.57+\:2.73\:+3.75\:+2.27+\:2.75+\:4.00+\:4.22+\:3.88+\:4.35+\:3.41+\:4.57+\:2.38+\:3.73\:+2.75+\:3.47+\:3.06\\\\\sum x_i=56.68$

and the sum of their squares is

$\sum x_i^2=2.79^2\:+2.57^2+\:2.73^2\:+3.75^2\:+2.27^2+\:2.75^2+\:4.00^2+\:4.22^2+\:3.88^2+\:4.35^2+\:3.41^2+\:4.57^2+\:2.38^2+\:3.73^2\:+2.75^2+\:3.47^2+\:3.06^2\\\\\sum x_i^2=197.46$

(b)

The sample variance, denoted by $s^2$ , is given by

$s^2=\frac{S_{xx}}{n-1}$

where $S_{xx} =\sum x_i^2-\frac{(\sum x_i)^2}{n}$

Applying the above formula we get that

$S_{xx}=197.46-\frac{(56.68)^2}{17}\\\\S_{xx} =8.482$

$s^2=\frac{8.482}{17-1}=0.530$

The sample standard deviation, denoted by <em>s</em>, is the (positive) square root of the variance:

$s=\sqrt{s^2}$

Applying the above formula we get that

$s=\sqrt{0.530}=0.728$

3 0

3 years ago

What is the complex conjugate of 7 + 8i ?

Lady bird [3.3K]

Answer:

7-8i

Step-by-step explanation:

to find as complex conjugate, simply change the sign of the imaginary pert (the part with the i). this means that is either goes from positive to negetive or from negetive to positive

as as general rule,the complex conjugate of a +bi is a-bi

3 0

3 years ago

15% of $9 is $______

Leona [35]

Answer:

$1.35

Step-by-step explanation:

multiply 9 by 15% which relates to .15. so 9×0.15 is $1.35

4 0

3 years ago

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How much interest will be earned on a $1600 investment at 7.72% compounded

frosja888 [35]

56% interest will be earned

3 0

3 years ago

Find the measures of the numbered angles in each kite.

Drupady [299]

Answer:

x = 15

y = 13

Step-by-step explanation:

6x - 4 = 5x + 11

x = 15

4y + 3 + 3y + 86 = 180

7y = 91

y = 13

7 0

3 years ago