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3 years ago

حل المعادلتين باستتخدام المعادله المصفوفه او الصف البسيط ٢م-ل=1 م+ل=٢-

Mathematics

1 answer:

Ket [755]3 years ago

4 0

Answer:

ummmm

Step-by-step explanation:

which language please and write in english so I will understand and after it all i will edit my answer

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If a straight line y = mx + c passes through the intersecting point of 3x - y = 8 and x+ 2y = 5 which is perpendicular to the li

Sindrei [870]

Answer:

Point of intersection:

$3x - y = 8 - - - (a) \\ x + 2y = 5 - - - (b)$

2 × equation(b) + equation (a):

$7x = 21 \\ x = 3 \\ \\ y = 3x - 8 \\ y = 1$

Point of intersection = (3, 1)

Perpendicular line:

$3x + 6y - 11 = 0 \\ 6y = - 3x + 11 \\ y = - \frac{1}{2} x + \frac{11}{6}$

General equation of line:

$y = mx + c \\ 1 = (2 \times 3) + c \\ c = - 5$

Value of m:

$m \times m {}^{i} = - 1 \\ m \times - \frac{1}{2} = - 1 \\ m = 2$

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3 years ago

On a standard IQ test, the standard deviation is 15. How many random IQ scores must be obtained if we want to find the true popu

igor_vitrenko [27]

Answer:

We need at least 4238 scores.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.97}{2} = 0.015$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.015 = 0.985$ , so $z = 2.17$

Now, find the margin of error M

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How many random IQ scores must be obtained if we want to find the true population mean (with an allowable error of 0.5) and we want 97 percent confidence in the results

We need at least n scores, in which N is found when $M = 0.5$ . So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.5 = 2.17*\frac{15}{\sqrt{n}}$

$0.5\sqrt{n} = 2.17*15$

$0.5\sqrt{n} = 32.55$

$\sqrt{n} = \frac{32.55}{0.5}$

$\sqrt{n} = 65.1$

$\sqrt{n}^{2} = (65.1)^{2}$

$n = 4238$

We need at least 4238 scores.

7 0

4 years ago

Solve the triangle given that a=19 b=16, c=11.

kirill [66]

Answer:

The angles of the triangle are approximately 87.395º, 57.271º and 35.334º.

Step-by-step explanation:

From statement we know all sides of the triangle ( $a$ , $b$ , $c$ ), but all angles are unknown ( $A$ , $B$ , $C$ ). (Please notice that angles with upper case letters represent the angle opposite to the side with the same letter but in lower case) From Geometry it is given that sum of internal angles of triangles equal 180º, we can obtain the missing information by using Law of Cosine twice and this property mentioned above.