how I understood this is first understanding how a graph works. Once you understand that you can count 13 horizontal on the "X" Axis, then go 18 up on the "Y" axis. you should get a point in the upper left area and that area is called Quadrant 1. Say if 13 was negative instead of going horizontal east you would go horizontal west. And the point should end up in Quadrant 2. Any more questions feel free to ask me below.

8 0

2 years ago

9. 3x + 9y = 18<br> y = x + 2<br> Substitution method

777dan777 [17]

Answer:

x = 0

y = 2

Step-by-step explanation:

3x + 9y = 18 ---------eqn 1

y = x + 2---------eqn 2

Substitute eqn 2 into eqn 1, for the value of y

3x + 9( x + 2) = 18

3x + 9x + 18 = 18

12x + 18 = 18

12x = 18 -18

12x = 0

Divide both sides by 12 , to get the value of x.

12x/ 12 = 0/12

x = 0

Substitute x = 0 into eqn 2

y = x + 2

y = 0 +2

y = 2

Hint: to confirm the values

x = 0

y = 2

Let's take eqn 1 ,

3x + 9y = 18

3(0) + 9(2)

= 0 + 18

= 18

Correct

Let's take eqn 2

y = x + 2

Let's find y

y = 0 + 2

y = 2

Correct too

4 0

2 years ago