Each X and Y in the equations don't have a number in front of them so they are all considered 1.
D = 1*(-1) - 1*(-1) = -1 -1 = -2
The answer is -2
F+G:

Then, add the elements that occupy the same position:

Solve

So, we find the element at address h31:

In this case, position h31 is - 8.0
Answer by JKismyhusbandbae: 6n-16
Arithmetic Formula: 
Use the following formula to determine any number in an arithmetic sequence:
an = a1 + d (n – 1)
a1 = the first term.
d = common difference
n = term number
9/2 = 81/a....9 kids meals to 2 adult meals = 81 kids meals to a adult meals
cross multiply
9a = 2(81)
9a = 162
a = 162/9
a = 18...so there were 18 adult meals
ratio is : 81/18
Answer:
Angle A: 45, Angle B: 110, and Angle C: 25.
Step-by-step explanation:
A triangle is 180 degrees total. One angle is 25 degrees. 180- 25 leaves us with 155 degrees. We know that one angle is more than 65 degrees. 155-65 is 90. 90/2 is 45. Therefore, x= 45. Angle A: 45, Angle B: 110, and Angle C: 25. We can double check our work by adding 45+110+25= 180