4d2–15d+9=0 solve for d

d = -15 ± 9 / 8

Step-by-step explanation:

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d = 3 and d = 3/4

Step-by-step explanation:

This is a quadratic eqution.  Let's use the quadratic formula to solve it.

If ax^2 + bx + c = 0, then:

      -b ± √(b^2 - 4ac)

x =

                 2a

With a = 4, b = -15 and d = 9, we have:

      -(-15) ± √(225 - 4(4)(9) )        15 ±√81         15 ±9

d = = = = 24/8 and 6/8

                      2(4)                              8                   8

Simplifying these results, we get d = 3 and d = 3/4

b

step-by-step explanation:

b

the expected value of the random variable : 0, 1 and 2

step-by-step explanation: