What are the solutions of the equation x4 – 5x2 - 36 = 0? Use factoring to solve. A. x = +-2 and x = +-3
B. x = +-2i and x = +-3
C. x = +-2 and x = +-3i
D. x = +-2i and x = +-3i

x = -2i and x = 2i

x = 3 and x = - 3

Step-by-step explanation:

x^4 - 5x^2 - 36 = 0

let u = x^2 and substitute

we have:

u^2 - 5u - 36 = 0

(u - 9)(u + 4) = 0

u = 9 and u = - 4

substitute back for u

x^2 = 9

x = 3 and x = - 3

x^2 = -4 -- i am going to assume you've learned imaginary numbers; otherwise, you cannot take the square root of a negative number.

x = -2i and x = 2i

d. millimeters per hour.

step-by-step explanation:

we are given that,

carlo used a rain gauge to measure the amount of water his lawn is receiving from the sprinklers.

since, according to the options, we see that,

water cannot be measured by 'miles per hour', 'meters per second' and 'grams per seconds'.

we get that, the water can be measured by 'millimeters per hour'.

hence, the appropriate rate for describing the amount of water is 'millimeters per hour'.