Answer: “P hay Q” là một mệnh đề được
Step-by-step explanation: Các quy tắc tương đương logic: ... Chứng minh biểu thức mệnh đề (¬((r ∨ q) ∧ q) ∨. ¬p)∧ ((¬p
Answer:
!["i"](https://tex.z-dn.net/?f=%22i%22)
Step-by-step explanation:
![i =\sqrt{-1} \\i^{2}= -1\\\\i^{3}= -i\\\\i^{4}= 1\\\\i^{5}= i\\](https://tex.z-dn.net/?f=i%20%3D%5Csqrt%7B-1%7D%20%5C%5Ci%5E%7B2%7D%3D%20-1%5C%5C%5C%5Ci%5E%7B3%7D%3D%20-i%5C%5C%5C%5Ci%5E%7B4%7D%3D%201%5C%5C%5C%5Ci%5E%7B5%7D%3D%20i%5C%5C)
the cycle repeats every 4
19/4 = 4.75
16 is divisible by 4 plus three more
thus
but you problem has a minus in front so "i"
Order of operations is one way
The correct answer is d.We have the following system of linear equations:
(I)
![4x+7y=-14](https://tex.z-dn.net/?f=4x%2B7y%3D-14)
(II)
![8x+5y=8](https://tex.z-dn.net/?f=8x%2B5y%3D8)
Let's use the elimination method, then let's multiply the equation (1)
![\times(-2)](https://tex.z-dn.net/?f=%5Ctimes%28-2%29)
and subtracting (I) and (II):
(I)
![-2(4x+7y)=-2(-14)](https://tex.z-dn.net/?f=-2%284x%2B7y%29%3D-2%28-14%29)
∴
![-8x-14y=28](https://tex.z-dn.net/?f=-8x-14y%3D28)
(I)
![-8x-14y=28](https://tex.z-dn.net/?f=-8x-14y%3D28)
(II)
![8x+5y=8](https://tex.z-dn.net/?f=8x%2B5y%3D8)
____________________
(III)
![-9y=36](https://tex.z-dn.net/?f=-9y%3D36)
∴
![y=-4](https://tex.z-dn.net/?f=y%3D-4)
We can find the value of x by substituting y either in (I) or (II). Thus, from (I):
![4x+7(-4)=-14](https://tex.z-dn.net/?f=4x%2B7%28-4%29%3D-14)
∴
![4x-28=-14](https://tex.z-dn.net/?f=4x-28%3D-14)
∴
![4x=14](https://tex.z-dn.net/?f=4x%3D14)
∴
![x=\frac{14}{4}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B14%7D%7B4%7D)
∴
![\boxed{x=\frac{7}{2}}](https://tex.z-dn.net/?f=%5Cboxed%7Bx%3D%5Cfrac%7B7%7D%7B2%7D%7D)
Let's substitute the values of x and y into (I) and (2)
(I)
![4(\frac{7}{2})+7(-4)=14-28=-14](https://tex.z-dn.net/?f=4%28%5Cfrac%7B7%7D%7B2%7D%29%2B7%28-4%29%3D14-28%3D-14)
(II)
![8(\frac{7}{2})+5(-4)=28-20=8](https://tex.z-dn.net/?f=8%28%5Cfrac%7B7%7D%7B2%7D%29%2B5%28-4%29%3D28-20%3D8)
Finally the answer is: