1 electron has a mass of 9.1 X 10-31 kg. How many electrons n does it take to make 1 kg?
(1 e)/(9.1 X 10-31 kg) = n/(1 kg)
So, n = 1.10 X 1030 electrons
Each electron has a charge of 1.6 X 10-19 C, where C stands for Coulombs. So, the n electrons have a charge of q = ne = (1.10 X 1030 electrons) X (1.6 X 10-19 C/electron) = 1.76 X 1011 C.
Let's form the difference of the two expressions and see what we can learn.
(2y -x) -(2x -y) = 2y -x -2x +y = 3y -3x = 3(y -x)
Since y > x, this is positive, so 2y -x is greater than 2x -y.
The answer is <span>c. 16x2 + 24xy + 9y2.
Since we need trinomial (three term expression) choices a and b are incorrect because they have only two terms.
So, our square trinomial is a</span>² + 2ab + b² or a² - 2ab + b²
a² + 2ab + b² = (a + b)²
a² - 2ab + b² = (a - b)²
Let's check choices c and d:
c) 16x² + 24xy + 9y²
a² = 16x²
a² = (4x)²
a = 4x
b² = 9y²
b² = (3y)²
b = 3y
a² + 2ab + b² = (4x)² + 2 * 4x * 3y + (3y)² = 16x² + 24xy + 9y²
CORRECT
d) 49x² - 70xy + 10y²
a² = 49x²
a² = (7x)²
a = 7x
b² = 10y²
b² = (y√10)²
b = y√10
a² + 2ab + b² = (7x)² + 2 * 7x * y√10 + (y√10)² = 49x² + 14xy√10 + 10y²
INCORRECT
So, c) is correct answer
Answer:
5 hours
Step-by-step explanation:
4/5 is 20 of 25, so there are 5 hours left which is your answer!
