Your answer would be C. 27/190.
This is because the probability of choosing green as the first marble would be 9/20, as there are 20 marbles in total and 9 of those are green.
The probability of choosing a red marble as the second marble would be 6/19, as no red marbles would have been lost if green was picked first, but there would be one less marble in total.
The 'and' rule for probability, the one that is used to determine the probability of P(A) and P(B), is to multiply, so we need to do 9/20 × 6/19 = 54/380 = 27/190.
I hope this helps!
The row echelon form of the matrix is presented as follows;

<h3>What is the row echelon form of a matrix?</h3>
The row echelon form of a matrix has the rows consisting entirely of zeros at the bottom, and the first entry of a row that is not entirely zero is a one.
The given matrix is presented as follows;

The conditions of a matrix in the row echelon form are as follows;
- There are row having nonzero entries above the zero rows.
- The first nonzero entry in a nonzero row is a one.
- The location of the leading one in a nonzero row is to the left of the leading one in the next lower rows.
Dividing Row 1 by -3 gives:

Multiplying Row 1 by 2 and subtracting the result from Row 2 gives;

Subtracting Row 1 from Row 3 gives;

Adding Row 2 to Row 3 gives;

Dividing Row 2 by -2, and Row 3 by 18 gives;

The above matrix is in the row echelon form
Learn more about the row echelon form here:
brainly.com/question/14721322
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Answer:
because a positive is over zero and a negative is below zero so from that you can tell that the opposite of any positive will be a negative.
Step-by-step explanation:
y = 3x - 1
x - y = -9
Subs y in second equation.
x - (3x - 1) = -9
x - 3x + 1 = -9
-2x = -9 - 1
-2x = -10
x = -10/-2
x = 5
Subs x
y = 3x - 1
y = 3.5 - 1
y = 15 - 1
y = 14
All of the angles in a triangle should add up to 180 degrees so if you know 2 out of three you just do subtract 180 by the sum of the two angles.
180-85=95