18. Which ordered pair is a solution of the system of linear equations listed below? 2x + y = -5
-x+3y=6
A. (-3, 1)
B. (3, 1)
C. (-3,-1)
D. (-1,3)​

A

Step-by-step explanation:

Given the 2 equations

2x + y = - 5 → (1)

- x + 3y = 6 → (2)

Multiplying (2) by 2 and adding to (1) will eliminate the x- term

- 2x + 6y = 12 → (3)

Add (1) and (3) term by term to eliminate x

0 + 7y = 7

7y = 7 ( divide both sides by 7 )

y = 1

Substitute y = 1 into either of the 2 equations and solve for x

Substituting into (1)

2x + 1 = - 5 ( subtract 1 from both sides )

2x = - 6 ( divide both sides by 2 )

x = - 3

solution is (- 3, 1 ) → A

Hi there!

length = 9 kilometres
Width = 12 kilometres

Let's solve this problem step by step!
To find our answer we need to set up and solve an equation.

Let the length of the rectangle be represented by x.
The width of the rectangle can therefore be expressed by 2x - 6.

The area of a rectangle can be found by using the formula:
A = width × length

Plug in the data from the formula
A = x (2x - 6).

Simplify using rainbow technique.


Now we've found the simplified expression that expresses the area of the rectangle. Therefore, we can now set up and start solve the equation.


Subtract 108


Divide by 2.



Rule AB = 0, gives A is 0 or B is 0.



The length of the rectangle, which was represented by x, must be 9 (since it cannot be a negative number).

Length

Width


length = 9 kilometres
Width = 12 kilometres

~ Hope this helps you!