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2 years ago

Seven less than two times a number is 29.

1 answer:

4 0

2x-7=29

"Seven less than" => minus 7.
"Two times <u>a number</u>" => 2x (x is the unknown number)
"is twenty-nine" => =29
Putting it all together,

-7 + 2x = 29
or
2x-7=29
(if you were wondering x is equal to 18)

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What is the equation of a line that passes through the points (3, 6) and (8, 4) in slope intercept form?

MrMuchimi

Answer:

$y=-\frac{2}{5}x +8.4$

Step-by-step explanation:

Gradient

$m =\frac{y-y1}{x-x1}$

$m = \frac{6-4}{3-8}$

$m=-\frac{2}{5}$

Equation of a line

$(y-y1)=m(x-x1)\\$

- Sub one set of points into equation

$(y-6)= -\frac{2}{5} (x-6)$

$y=-\frac{2}{5}x +8.4$

6 0

3 years ago

Complete the coordinate proof of the theorem.

mojhsa [17]

C(a,b), because the x-coordinate( first coordinate) is a (seeing as it is situated directly above point B, which also has an x-coordinate of a) and the y-coordinate ( second coordinate) is b (seeing as it is situated on the same horizontal level as point D, which also has a y-coordinate of b)

the length of AC can be calculated with the theorem of Pythagoras:

length AB = a - 0 = a
length BC = b - 0 = b

seeing as the length of AC is the longest, it can be calculated by the following formula:

It is called "Pythagoras' Theorem" and can be written in one short equation:

a^2 + b^2 = c^2 (^ means to the power of by the way)

in this case, A and B are lengths AB and BC, so lenght AC can be calculated as the following:

a^2 + b^2 = (length AC)^2
length AC = √(a^2 + b^2)

Extra information: Seeing as the shape of the drawn lines is a rectangle, lines AC and BD have to be the same length, so BD is also √(a^2 + b^2). But that is also stated in the assignment!

3 0

3 years ago

Read 2 more answers

The sum of the measures of two adjacent angles is 72 degrees. The ratio of the smaller angle to the

Goryan [66]

Answer:

The larger angle is 54°

Step-by-step explanation:

Given

Let the angles be: θ and α where

θ > α

Sum = 72

α : θ = 1 : 3

Required

Determine the larger angle

First, we get the proportion of the larger angle (from the ratio)

The sum of the ratio is 1 + 3 = 4

So, the proportion of the larger angle is ¾.

Its value is then calculated as:.

θ = Proportion * Sum

θ = ¾ * 72°

θ = 3 * 18°

θ = 54°

4 0

2 years ago

Find the critical points of the function f(x, y) = 8y2x − 8yx2 + 9xy. Determine whether they are local minima, local maxima, or

NARA [144]

Answer:

Saddle point: $(0,0)$

Local minimum: $(\frac{3}{8}, -\frac{3}{8})$

Local maxima: $(0,-\frac{9}{8})$ , $(\frac{9}{8},0)$

Step-by-step explanation:

The function is:

$f(x,y) = 8\cdot y^{2}\cdot x -8\cdot y\cdot x^{2} + 9\cdot x \cdot y$

The partial derivatives of the function are included below:

$\frac{\partial f}{\partial x} = 8\cdot y^{2}-16\cdot y\cdot x+9\cdot y$

$\frac{\partial f}{\partial x} = y \cdot (8\cdot y -16\cdot x + 9)$

$\frac{\partial f}{\partial y} = 16\cdot y \cdot x - 8 \cdot x^{2} + 9\cdot x$

$\frac{\partial f}{\partial y} = x \cdot (16\cdot y - 8\cdot x + 9)$

Local minima, local maxima and saddle points are determined by equalizing both partial derivatives to zero.

$y \cdot (8\cdot y -16\cdot x + 9) = 0$

$x \cdot (16\cdot y - 8\cdot x + 9) = 0$

It is quite evident that one point is (0,0). Another point is found by solving the following system of linear equations:

$\left \{ {{-16\cdot x + 8\cdot y=-9} \atop {-8\cdot x + 16\cdot y=-9}} \right.$

The solution of the system is (3/8, -3/8).

Let assume that y = 0, the nonlinear system is reduced to a sole expression:

$x\cdot (-8\cdot x + 9) = 0$

Another solution is (9/8,0).

Now, let consider that x = 0, the nonlinear system is now reduced to this:

$y\cdot (8\cdot y+9) = 0$

Another solution is (0, -9/8).

The next step is to determine whether point is a local maximum, a local minimum or a saddle point. The second derivative test:

$H = \frac{\partial^{2} f}{\partial x^{2}} \cdot \frac{\partial^{2} f}{\partial y^{2}} - \frac{\partial^{2} f}{\partial x \partial y}$

The second derivatives of the function are:

$\frac{\partial^{2} f}{\partial x^{2}} = 0$

$\frac{\partial^{2} f}{\partial y^{2}} = 0$

$\frac{\partial^{2} f}{\partial x \partial y} = 16\cdot y -16\cdot x + 9$

Then, the expression is simplified to this and each point is tested:

$H = -16\cdot y +16\cdot x -9$

S1: (0,0)

$H = -9$ (Saddle Point)

S2: (3/8,-3/8)

$H = 3$ (Local maximum or minimum)

S3: (9/8, 0)

$H = 9$ (Local maximum or minimum)

S4: (0, - 9/8)

$H = 9$ (Local maximum or minimum)

Unfortunately, the second derivative test associated with the function does offer an effective method to distinguish between local maximum and local minimums. A more direct approach is used to make a fair classification:

S2: (3/8,-3/8)

$f(\frac{3}{8} ,-\frac{3}{8} ) = - \frac{27}{64}$ (Local minimum)