What is the coefficient of x 9y 4 in the expansion of (2x + 3y) 13?

  29,652,480

Step-by-step explanation:

The term of interest is ...

  (13C9)(2x)^9·(3y)^4 = 715·512·81·x^9·y^4 = 29,652,480·x^9·y^4

The coefficient is 29,652,480.

x = ± 6i

step-by-step explanation:

x^2 = -36

take the square root of each side

sqrt(x^2) = sqrt(-36)

we know sqrt(ab) = sqrt(a) sqrt(b)

x = ±sqrt(36) sqrt(-1)

we know that sqrt (-1) = i

x = ± 6i