I don’t really understand for question 11 to 13
Answer:
C
Step-by-step explanation:
I did the test
Shown below
<h2>
Explanation:</h2>
In this exercise, we have the following system of linear equations in two variables:

From the first equation:

Here as x increases one unit, then y decreases by one unit too. Therefore, if (0, 5) is a point on the line, then (1, 4) is also a point on the line. From here, we know that the line must pass through these two points.
From the second equation:

Here as x increases 4 units, then y increases by one unit Therefore, if (0, 10) is a point on the line, then (4,11) is also a point on the line. From here, we know that the line must pass through these two points.
By using graphing tool, we realize that both graphs intersect at a single point, which is:

The graph is shown below.
<h2>Learn more:</h2>
System of linear equations: brainly.com/question/13799715
#LearnWithBrainly
Answer:
-27
Step-by-step explanation:
Number be x
Eight added to number: x+8
sum is doubled: 2*(x + 8)
-11 less than number: x -11
2*(x + 8) = x -11
2*x + 2*8 = x - 11
2x + 16 = x - 11
2x - x = -11 -16
x = -27