Answer:
The answer to your question is below
Step-by-step explanation:
15. x² = 144
x = √144
x = ± 12
19. 9x² = 4
x² = 4/9
x = √4/9
x = ± 2/3
20.
25y² = -16
y² = -16/25
y = √-16/25
y = ± 4/5 i
21. 16y² = 25
y² = 25/16
y = √25/16
y = ±5/4
25.
81 - 9x² = 0
81 = 9x²
81/9 = x²
9 = x²
√9 = x
x = ± 3
