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stellarik [79]
3 years ago
11

3x^2-12x-21=0 solve by completing the square

Mathematics
1 answer:
morpeh [17]3 years ago
3 0

Answer:

x = 2 ± √11 (I believe)

Step-by-step explanation:

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This figure is made up of a rectangle and parallelogram.
ivann1987 [24]

The area of the figure is 40 units. (rounded off from 39.998 units)

Step-by-step explanation:

1. Area of the figure = Area of Rectangle + Area of Parallelogram.

2. Naming points:

Let the rectangle consist of points A(-6,-1), B(-5,-5), C(3,-3) and D(2,1).

Let the parallelogram consist of points C(3,-3), D(2,1), E(2,7) and F(3,3).

3. Each coordinate has a point on the x-axis and a point on the y-axis. We shall refer to these points as x', x'' ,x''' and so on corresponding to the x-axis values of A, B, C and so on in that order till F. For the y-axis points, we will name them in the series of y', y'', y''' and so on.

In simple words, in A(-6,1), x' = -6; y' = -1

4. Formula for finding area:

Area of a rectangle = length (l) × width (w)

Area of a parallelogram = base (b) x height (h)

5. Finding area of the rectangle:

l = AD = \sqrt{[x'''' - x']^{2} - [y'''' - y']^{2}}

, i.e. AD = \sqrt{[2 - (-6)]^{2} - [1 - (-1)]^{2}}

, i.e. AD = √68 = 8.246 (rounded to 3 decimals) = l

Now, w = AB = \sqrt{[x'' - x']^{2} - [y'' - y']^{2}}

, i.e. AB = \sqrt{[(-5) - (-6)]^{2} - [(-5) - (-1)]^{2}}

, i.e. AB = √17 = 4.123 (rounded to 3 decimals) = w

Area of rectangle = l x w = 8.246 x 4.123 = 33.998 units.

6. Finding area of the parallelogram:

b = DE = 6 units (we can observe this from the graph, i.e. points from 1 to 7 on the y axis)

h = Height is the line drawn perpendicular to the base from point F, which as we can see is 1 unit long.

Hence, Area of parallelogram = b x h = 6 x 1 = 6 units.

7. Now, adding both, we can arrive at the final answer.

Area of the figure = Area of rectangle + Area of parallelogram,

i.e. 33.998 units + 6 units = 39.998 units. (can be rounded off to 40 units)

4 0
3 years ago
Evaluate 3z when z=9
sweet-ann [11.9K]
Z=9 so 3*9 is 27. 27 is your answer. You are literally just switching the variable z with 9.
3 0
3 years ago
Read 2 more answers
Sin∅=3/5, then cos∅=_____
alexandr1967 [171]

Answer:

4/5.

Step-by-step explanation:

The right triangle with this angle in it has sides 3, 4 and 5.  ( 5^2 = 3^2 + 4^2).

So as sin∅ = 3/5,  the opposite side to angle ∅ is 3 , the hypotenuse is 5 and the adjacent side must be 4 units long.

So cos∅ = adjacent side/hypotenuse = 4/5.

7 0
3 years ago
1. Using the side lengths, determine whether the triangle is acute, obtuse, or right.
pav-90 [236]

Answer:

Obtuse

Step-by-step explanation:

6 0
3 years ago
There are 3 feet in 1 yard. Find the number of feet in a 15-yard run by a football player
Nadusha1986 [10]

Answer: 5 feet

Step-by-step explanation:

15 divided by 3

6 0
3 years ago
Read 2 more answers
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