Answer: a + b = 3 - [tex]\sqrt{2ab}[/tex] maybe
Step-by-step explanation:
( 3a + 3b + 1 )( 3a + 3b - 1 ) = 80
Expand
9a² + 9ab - 3a + 9ab + 9b² - 3b + 3a + 3b - 1 = 80
Simplify
9a² + 9b² + 18ab - 1 = 80
move the 1 over
9a² + 9b² + 18ab = 81
divide by 9
a² + b² + 2ab = 9
not really sure after this part
move the 2ab over
a² + b² = 9 - 2ab
square root both sides
a + b = [tex]\sqrt{9-2ab}[/tex]
simplify
a + b = 3 - [tex]\sqrt{2ab}[/tex]
