Answer:
The correct option is C: the isotope of iodine contains 81 neutrons.
Step-by-step explanation:
The mass (A) of the iodine isotope is given by:
Where:
Z: is the number of protons
N: is the number of neutrons
For iodine Z= 53, so if A = 134 the number of neutrons is:
Therefore, the correct option is C. The isotope of iodine contains 81 neutrons.
I hope it helps you!
Answer:
x = 387
Step-by-step explanation:
The wind acts in the opposite direction to the plane when the time is longer.
The wind acts in the same direction as the plane when the time is shorter.
Equation
d = r*t
Givens
- d = 1720
- x = plane's speed
- y = wind speed
- t1 = 5 hours
- t2 = 4 hours.
Substitution
- d = (x + y) * t
- 1720 = (x + y) * 4
- 1720 = (x - y) * 5
Since the two distances are the same, you can equate the right hand sides.
- (x + y) * 4 = (x - y)*5 Remove the brackets.
- 4x + 4y = 5x - 5y Add 5y to both sides
- 4x + 4y + 5y = 5x - 5y + 5y Combine all the terms.
- 4x + 9y = 5x Subtract 4x from both sides
- 9y + 4x - 4x = 5x - 4x Combine
- 9y = x
Now use one of the given equations with the distance
- 1720 = (x + y)*4 Substitute 9y for x
- 1720 = (9y + y) * 4 Combine
- 1720 = 10y * 4 Multiply the right
- 1720 = 40y Divide by 40
- 1720/40 = 40y/40 Do the division
- 43 = y y = wind speek
- 9y = x x = 9*y
- 9*43 = x
- x = 387 miles per hour.
Answer:
Algebrically the result can be written as -
Step-by-step explanation:
Let the number be 'x'.
- When multiplied by 3 , algebrically it is written as "3x".
- When 4 is added to 3x , algebrically it is written as "3x + 4".
- When (3x + 4) is squared completely , algebrically it is written as -
