Answer:

Step-by-step explanation:
Given:


Answer:
A
Step-by-step explanation:
brackets first according to bodmas
Answer:
It is a singular matrix system.
Step-by-step explanation:
A column of all zeros in a matrices says that the variable associated with that column has no effect on the output.
For example If the first column of a matrix consists of zeros, this means that the coefficient of the first variable is zero in every equation in the system . This means that if there is any solution at all, then there must be an infinite number of them, since you can set that first variable to any value at all and still satisfy all of the equations.
Answer:
D. 64
Step-by-step explanation:
Setup an equation to solve for the missing test, x. Since you are doing average and there are three tests, divide the left side of the equation by 3. Set the equation equal to 60 since that is what we want the average to be.

Multiply both sides by 3 to remove it from the denominator.


Simplify and solve for x.

Answer:
y = 3
Step-by-step explanation:
The side labeled 'y' is the 'adjacent side' of the 30° angle. The hypotenuse of this right triangle is 2√3.
The trig function relating this 30° angle, the 2√3 hypotenuse and the adj. side labeled 'y' is the cosine:
adjacent side y
cos 30° = ---------------------- = --------- , and the value of cos 30° is (√3)/2.
2√3 2√3
Solving for y, we get 2√3 (√3)/2, or y = 2(3)/2, or y = 3