Giá trị a, b để hệ phương trình ⎧⎩⎨x+2y+az=33x−y−az=22x+y+3z=bcó nghiệm duy nhất là Select one:

a.∀a, b∈R

b. a≠212v a` ∀b∈R

c. Không tồn tại a, b∈R

d. a=212v a` ∀b∈R

Which pair of lines is parallel? a. y=4x+1 and y+4=5 b. y=-2+x and 2y-2x=-2 c. y=1/4x + 2 and y-2=1/2x d. y=1/5x+1 and 5y+x= 10

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

Math each whole number with a rational, exponential expression