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3 years ago

Solve the equation for x, where x is a real number (5 points): -4x^2 + 3x - 1 = 2

1 answer:

6 0

Subtract 2 to both sides so that the equation becomes -4x^2 + 3x - 3 = 0.
To find the solutions to this equation, we can apply the quadratic formula. This quadratic formula solves equations of the form ax^2 + bx + c = 0
                                     x = [ -b ± √(b^2 - 4ac) ] / (2a)
                                     x = [ -3 ± √((3)^2 - 4(-4)(-3)) ] / ( 2(-4) )
                                     x = [-3 ± √(9 - (48) ) ] / ( -8 )
                                     x = [-3 ± √(-39) ] / ( -8)
The answers to this question is that there are no real solutions since the discriminant is -39. √-39 is nonreal.

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A certain square is to be drawn on a coordinate plane. One of the vertices must be on the origin, and the square is to have an a

Scrat [10]

Answer:

The answer is (C) 8

Step-by-step explanation:

First, let's calculate the length of the side of the square.

$A_{square}=a^2$ , where $a$ is the length of the side. Now, let's try to build the square. First we need to find a point which distance from (0, 0) is 10. For this, we can use the distance formula in the plane:

$d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}$ which for $x_1=0$ and $y_1 = 0$ transforms as $d=\sqrt{(x_2)^2 + (y_2)^2}$ . The first point we are looking for is connected to the origin and therefore, its components will form a right triangle in which, the Pythagoras theorem holds, see the first attached figure. Then, $x_2$ , $y_2$ and 10 are a Pythagorean triple. From this, $x_2= 6$ or $x_2=8$ while $y_2= 6$ or $y_2=8$ . This leads us with the set of coordinates:

$(\pm 6, \pm 8)$ and $(\pm 8, \pm 6)$ . (A)

The next step is to find the coordinates of points that lie on lines which are perpendicular to the lines that joins the origin of the coordinate system with the set of points given in (A):

Let's do this for the point (6, 8).

The equation of the line that join the point (6, 8) with the origin (0, 0) has the equation $y = mx +n$ , however, we only need to find its slope in order to find a perpendicular line to it. Thus,

$m = \frac{y_2-y_1}{x_2-x_1} \\m = \frac{8-0}{6-0} \\m = 8/6$

Then, a perpendicular line has an slope $m_{\bot} = -\frac{1}{m} = -\frac{6}{8}$ (perpendicularity condition of two lines). With the equation of the slope of the perpendicular line and the given point (6, 8), together with the equation of the distance we can form a system of equations to find the coordinates of two points that lie on this perpendicular line.

$m_{\bot}=\frac{6}{8} = \frac{8-y}{6-x}\\ 6(6-x)+8(8-y)=0$ (1)

$d^2 = \sqrt{(y_o-y)^2+(x_o-x)^2} \\(10)^2=\sqrt{(8-y)^2+(6-x)^2}\\100 = \sqrt{(8-y)^2+(6-x)^2}$ (2)

This system has solutions in the coordinates (-2, 14) and (14, 2). Until here, we have three vertices of the square. Let's now find the fourth one in the same way we found the third one using the point (14,2). A line perpendicular to the line that joins the point (6, 8) and (14, 2) has an slope $m = 8/6$ based on the perpendicularity condition. Thus, we can form the system:

$\frac{8}{6} =\frac{2-y}{14-x} \\8(14-x) - 6(2-y) = 0$ (1)

$100 = \sqrt{(14-x)^2+(2-y)^2}$ (2)

with solution the coordinates (8, -6) and (20, 10). If you draw a line joining the coordinates (0, 0), (6, 8), (14, 2) and (8, -6) you will get one of the squares that fulfill the conditions of the problem. By repeating this process with the coordinates in (A), the following squares are found:

(0, 0), (6, 8), (14, 2), (8, -6)

(0, 0), (8, 6), (14, -2), (6, -8)
(0, 0), (-6, 8), (-14, 2), (-8, -6)
(0, 0), (-8, 6), (-14, -2), (-6, -8)

Now, notice that the equation of distance between the two points separated a distance of 10 has the trivial solution $(\pm10, 0)$ and $(0, \pm10)$ . By combining this points we get the following squares:

(0, 0), (10, 0), (10, 10), (0, 10)
(0, 0), (0, 10), (-10, 10), (-10, 0)
(0, 0), (-10, 0), (-10, -10), (0, -10)
(0, 0), (0, -10), (-10, -10), (10, 0)

See the attached second attached figure. Therefore, 8 squares can be drawn

8 0

3 years ago

What is 20% of 50 (show work)

seraphim [82]

X/50 = 20/100

its takes adding 30 to 20 to get to 50 so add 30 to 100 then its 130/100 (130 over 100) and then divide that and its 13 = 13%

i think its right dont hold it against me if im wrong

8 0

3 years ago

A number is divided by 18 the result is 20 what is the number<br>

Basile [38]

Answer:

360

Step-by-step explanation:

You can solve this by doing 18 times 20 is 360: and then dividing 360 by 18, results in 20.

3 0

3 years ago

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Describe the image of D first reflected across line l, then across line m.

Basile [38]

Answser: the image of D will be the same drawing (D), translated to the right of the line m.

Explanation:

1) The first reflection, accross the line l, will be the letter<span> D turned (with the "belly" to the left instead of the right), located to the right of the line l and to the left of the line m.

2) The second reflection, accross the line m, will turn the letter again leting it equal to the original picture, now translated to the right on the line m.

</span>

5 0

3 years ago

Nilai dari x memenuhi pertidaksamaan [x-1]<2

slega [8]

Answer:

Step-by-step explanation:

4 0

3 years ago

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