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3 years ago

Find two square roots of 81

Mathematics

2 answers:

Alla [95]3 years ago

8 0

nine and negative nine

Bad White [126]3 years ago

3 0

Well if you think about if 9 times 9 equals 81. -9 and -9 also equals 81 because negative times negative equals positive 81

You might be interested in

If 5-y^2=x^2 then find d^2y/dx^2 at the point (2, 1) in simplest form.

ratelena [41]

Answer:

y"(2, 1) = -5

Step-by-step explanation:

Step 1: Define implicit differentiation

5 - y² = x²

Step 2: Find dy/dx

Take implicit differentiation: -2yy' = 2x
Isolate y': y' = 2x/-2y
Isolate y': y' = -x/y

Step 3: Find d²y/dx²

Quotient Rule: y'' = [y(-1) - y'(-x)] / y²
Substitute y': y" = [-y - (-x/y)(-x)] / y²
Simplify: y" = [-y - x²/y] / y²
Multiply top/bottom by y: y" = (-y² - x²) / y³
Factor negative: y" = -(y² + x²) / y³

Step 4: Substitute and Evaluate

y"(2, 1) = -(1² + 2²) / 1³

y"(2, 1) = -(1 + 4) / 1

y"(2, 1) = -5/1

y"(2, 1) = -5

3 0

3 years ago

The coordinates of polygon ABCD are A(-4,-1), B(-2,3), C(2,2), and D(4,-3). Use these coordinates to complete the sentences belo

PolarNik [594]

Answer:

The perimeter of polygon ABCD, to the nearest thousandth units is

22.227 units

The perimeter of polygon ABCD', to the nearest thousandth, would be 20.980 units

The area of polygon ABCD' is 19.5 units²

Step-by-step explanation:

The coordinates forming the polygon are

A (-4,-1), B(-2,3), C(2,2), and D(4,-3)

The perimeter then is given by the sum of the length of the sides as follows;

Length of line between two X and Y points distance, xi and yj apart is

length XY = $\sqrt{x^2+y^2}$

Therefore, the length between points AB is

length AB = $\sqrt{(-4 - (-2))^2+(-1-3)^2}$

= $\sqrt{(-4 +2)^2+(-4)^2} = \sqrt{-2^2+-4^2} = \sqrt{20}$ = 4.472 units

Similarly, length BC is given by

Length BC = $\sqrt{(-4)^2+1^2} = \sqrt{17}$ = 4.123 units

Length CD = $\sqrt{(-2)^2+5^2} = \sqrt{29}$ = 5.385 units

Length DA = $\sqrt{(8)^2+(-2)^2} = \sqrt{68}$ = 8.246 units

The perimeter is equal to;

length AB + Length BC + Length CD + Length DA

= 4.472 + 4.123 + 5.385 + 8.246 = 22.227 units

If the point D is moved up 2 units and left 1 unit we have

D' = x-1, y+2 where x and y are the coordinates of point D

D(4, -3) → D'((4-1), (-3+2)) = D'(3, -1)

The length D'A = $\sqrt{(7)^2+(0)^2} = \sqrt{49}$ =7 units

The perimeter of polygon ABCD'

length AB + Length BC + Length CD + Length D'A

= 4.472 + 4.123 + 5.385 + 7 = 20.980 units.

The area is given by the determinant of the 3 by 3 matrix using Cramer's Rule as follows

$S_{\bigtriangleup}$ = $(\frac{1}{2})|x_1y_2+x_2y_3+x_3y_1-x_1y_3-x_2y_1-x_3y_2|$

= $(\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|$

Triangle ABC we have

A(-4,-1)

B(-2,3)

C(2,2)

$S_{{\bigtriangleup}ABC}$ = $(\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|$

$=(\frac{1}{2})|(-4)(3-2)+(-2)(2-(-1)) +2((-1)-3)|$

= $=(\frac{1}{2})|-4-6 -8|= 9 units^2$

Triangle ACD'

A(-4,-1)

C(2,2)

D'(3, -1)

$S_{{\bigtriangleup}ACD'}$ = $(\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|$

$=(\frac{1}{2})|(-4)(2+1)+(2)(-1+1) +3((-1)-2)| = \frac{21}{2}$ = 10.5 units²

Area of polygon = $S_{{\bigtriangleup}ABCD'}$ = $S_{{\bigtriangleup}ABC}$ + $S_{{\bigtriangleup}ACD'}$ = (9 + 10.5) units²

Area of polygon ABCD' = 19.5 units².

8 0

4 years ago

The price was

ryzh [129]

Answer: $165

Step-by-step explanation: Divide the new price by 1, + the percent of increase. 198 / 1.20 = 165

<u><em>MARK AS BRAINLIEST PLEASE! ;D</em></u>

8 0

3 years ago

what is the difference between all real numbers and no solution how do you know when these situations occur

Naddik [55]

For a solution of 'all real numbers' to occur, you must end up with a statement that is true no matter what

example
simplifying results in x=x or 8=8 or 0=0 or something liek that

an example equation would be 2(x+1)=2x+2, simplifies to x=x or 2=2 or 0=0

no solution is when you get a false statement from simplifying
example, 3=4 or -1=0

an example equation could be 2(x+1)=2x+3, it simplifies to 2=3 which is false

4 0

3 years ago

If the two prisms have equal heights and volumes, what is the length of the x in Prism II?

m_a_m_a [10]

The volume of a prism is given by

$V = A_b\cdot h$