This math is just too much and makes little to no sense.
Use the formula:

B refers to the base and H refers to the height of the triangle.
As such, multiply both the base and height of the triangle and divide the answer by 2, to find the area of the triangle.
Answer:
22
Step-by-step explanation:
Find f(-3) :
f(x) = x² + 2x for x ≤ -3
That means for those values of x, less than or equal to -3, this is the function.
So, f(-3) = (-3)² + 2(-3) = 9 - 6 = 3
Now, f(-1) :
From the given data, we see it is: f(x) = 2
We take this because -1 lies between -3 and 4.
Now, f(-1) = 2
=>
For f(4) :
Clearly, the function is:
Therefore, <u>f(-3) + f(-1) - f(4) = 3 + 18 - (-1) = 3 + 18 + 1 = 22.</u>
From all those aforementioned, the true statement is: Thanh’s grade is 2.5 standard deviations below the mean of the test grades.
Answer:
Please refer to the attachment