A bank gives each new customer a 4 digit code number which alllows the new customer to create their own password. The code number is assigned randomly from the digits 1,3,5,and 7. No digit is repeated. what is the probablity that the code number for a customer will begin at 7?

it is true

step-by-step explanation:

all the combinations add up i used   calculator

c - they will have the same distribution

step-by-step explanation:

this is the only one that could make sense. : )

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81