2/5
Since 12 out of 30 marbles were black, you can assume that the percentage of black marbles in the bag is 40% (Ex: 12/30=.4) The probability that the marble you pick is black is equal to the percentage of black marbles in the bag. 40% is equal to 2/5.
The number of terms in the expression given is; 2.
<h3>How many term are in the expression given?</h3>
It follows from the task content that the expression given is; (3x^2-3)(3x^2+3).
It therefore follows the converse of law regarding difference of two squares that the expression given can be rewritten as;
= 9x⁴ -9
Read more on difference of two squares;
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180 degree rotation negates both coordinates, and takes a point from quadrant 2 to quadrant 4.
Answer: 4
We can also rotate 180 degrees clockwise, or 540 degrees counterclockwise and end up in the same place.
Combining transformations, we can reflect in the x axis and then in the y axis, also negating both coordinates so equivalent to 180 degree rotation.
28a⁴b: 2 · 2 · 7 · a · a · a · a · b
16ab: 2 · 2 · 2 · 2 · a · b
GCF(28a⁴b, 16ab) = 4ab
The answer is A.