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3 years ago

Use substitution to solve the system equation. n=3m-11 2m+3n=0

Mathematics

1 answer:

prohojiy [21]3 years ago

6 0

Answer:

m = 3, n = -2.

Step-by-step explanation:

Substitute n = 3m - 11 in the second equation:

2m + 3(3m - 11) = 0

2m + 9m - 33 = 0

11m = 33

m = 3.

Substitute for m in n = 3m-11:

n = 3(3) - 11

n = -2.

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The length,AB of the rectangular lot is 1 foot less than two times its width, BC. If the perimeter of the rectangular lot 394 fe

r-ruslan [8.4K]

Answer:

$AB=131\ ft$

Step-by-step explanation:

we know that

The perimeter of the rectangular lot is

$P=2(AB+BC)$ ----> equation A

where

AB is the length

BC is the width

we have

$AB=2BC-1$ ---> equation B

$P=394\ ft$ ----> equation C

substitute equation B and equation C in equation A

$394=2(2BC-1+BC)$

solve for BC

$394=2(3BC-1)$

$394=6BC-2$

$6BC=396$

$BC=66\ ft$

<em>Find the value of AB</em>

$AB=2BC-1$

$AB=2(66)-1$

$AB=131\ ft$

6 0

3 years ago

24 inches is 250% of what length

Alinara [238K]

The answer is: " 9.6 inches " .
________________________________________________________
Explanation:
________________________________________________________

24 = 250/100 * x ;

24 = 2.5 x ;

↔ 2.5 x = 24 ;

2.5 x / 2.5 = 24/ 2.5 ;

x = 9.6 ;

The answer is: " 9.6 inches <span>" .
</span>_________________________________________________________

4 0

3 years ago

Read 2 more answers

Solve the system by using a matrix equation (Picture provided)

Katyanochek1 [597]

Answer:

Option b is correct (8,13).

Step-by-step explanation:

7x - 4y = 4

10x - 6y =2

it can be represented in matrix form as $\left[\begin{array}{cc}7&-4\\10&-6\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{c}4\\2\end{array}\right]$

A= $\left[\begin{array}{cc}7&-4\\10&-6\end{array}\right]$

X= $\left[\begin{array}{c}x\\y\end{array}\right]$

B= $\left[\begin{array}{c}4\\2\end{array}\right]$

i.e, AX=B

or X= A⁻¹ B

A⁻¹ = 1/|A| * Adj A

determinant of A = |A|= (7*-6) - (-4*10)

= (-42)-(-40)

= (-42) + 40 = -2

so, |A| = -2

Adj A= $\left[\begin{array}{cc}-6&4\\-10&7\end{array}\right]$

A⁻¹ = $\left[\begin{array}{cc}-6&4\\-10&7\end{array}\right]$ / -2

A⁻¹ = $\left[\begin{array}{cc}3&-2\\5&-7/2\end{array}\right]$

X= A⁻¹ B

X= $\left[\begin{array}{cc}3&-2\\5&-7/2\end{array}\right] *\left[\begin{array}{c}4\\2\end{array}\right]$

X= $\left[\begin{array}{c}(3*4) + (-2*2)\\(5*4) + (-7/2*2)\end{array}\right]$

X= $\left[\begin{array}{c}12-4\\20-7\end{array}\right]$

X= $\left[\begin{array}{c}8\\13\end{array}\right]$

x= 8, y= 13

solution set= (8,13).

Option b is correct.

3 0

3 years ago

Find the approximate solution(s) to each of the following equations graphically. Use technology to support your

ser-zykov [4K]

Answer: x" = 5.69

Step-by-step explanation:

The graphic solution is attached.

Verifying the solution:

Existence condition: x > 0

2x - 4 = √x + 5

√x =2x - 4 - 5

√x =2x - 9 (²)

x = (2x - 9)²

x = 4x² - 36x + 81

4x² - 36x - x + 81 = 0

4x² - 37x + 81 = 0

Δ = -37² - 4.4.81 = 1369 - 1296 = 73

x = 37 ±√73/8

x' = 3.55

x" = 5.69

checking:

2*3.55 - 4 = 3.1

√3.55 + 5 = 6.88 Its not the same ∴ 3.55 is not a solution

2*5.69 - 4 = 7.39

√5.69 + 5 = 7.39 ∴ it's the only solution

4 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

3 years ago