Question

Answers to questions 15,19,20,21 &25

Answer 1

The answer to your question is below

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