It should be 13 since 13+8 = 21. 21-7 = 13
Answer:
15.07352941
Step-by-step explanation:
in short 15.07
<h2>
Hello!</h2>
The answer is:
The correct option is the first option:

<h2>
Why?</h2>
To write the equation of the line in slope-interception form we need to extract all the information that we need from the graphic.
We must remember that the slope-interception form of the lines is:

Where,
y, is the function
m, is the slope of the line
x, is the variable
b, is the y-axis intercept
We can find the slope using the following formula:

Which is for this case:

As we can see from the graphic, the line is decresing, so the sign of the slope "m" will be negative, so:

We can find the value of "b" seeing where the line intercepts the y-axis.
As we can see it intercept the y-axis at: 
Then, now that we already know the value of "m" and "b", we can write the equation of the line:

So, the correct option is the first option:

Have a nice day!
Step-by-step explanation:
Triangle XYZ is isosceles.
Since Angle Y = 90°, Angle Z = (180° - 90°)/2 = 45°.