Question

What are the solutions of the equation 9x4 – 2x2 – 7 = 0? Use u substitution to solve.x = + √7/9 and x = ±1 x = + √7/9 and x = ±i x = +i √7/9 and x = ±1 x = +i √7/9 and x = ±I 

Answer 1

Answer:

Step-by-step explanation:

9x⁴ – 2x² – 7 = 0

Let's say that u = x²:

9u² – 2u – 7 = 0

Factor:

(u – 1) (9u + 7) = 0

u = 1, -7/9

Since u = x²:

x² = 1, -7/9

x = ±1, ±i √(7/9)

Answer 2

Answer:

the answer is c on edgenunity

Step-by-step explanation: