Answer :
Answer:
u = x²
Step-by-step explanation:
4x⁴ − 21x² + 20 = 0
Substitute u = x² to turn the equation into a quadratic.
4u² − 21u + 20 = 0
You can solve by factoring.
(4u − 5) (u − 4) = 0
u = 5/4 or 4
x² = 5/4 or 4
x = ±½√5 or ±2
Answer:
u = x²
Step-by-step explanation:
4x⁴ − 21x² + 20 = 0
Substitute u = x² to turn the equation into a quadratic.
4u² − 21u + 20 = 0
You can solve by factoring.
(4u − 5) (u − 4) = 0
u = 5/4 or 4
x² = 5/4 or 4
x = ±½√5 or ±2
