Answer:
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
