(3+a)*(3-a)=6

Solution for (3+a)*(3-a)=6 equation:

Simplifying
(3 + a)(3 + -1a) = 6

Multiply (3 + a) * (3 + -1a)
(3(3 + -1a) + a(3 + -1a)) = 6
((3 * 3 + -1a * 3) + a(3 + -1a)) = 6
((9 + -3a) + a(3 + -1a)) = 6
(9 + -3a + (3 * a + -1a * a)) = 6
(9 + -3a + (3a + -1a2)) = 6

Combine like terms: -3a + 3a = 0
(9 + 0 + -1a2) = 6
(9 + -1a2) = 6

Solving
9 + -1a2 = 6

Solving for variable 'a'.

Move all terms containing a to the left, all other terms to the right.

Add '-9' to each side of the equation.
9 + -9 + -1a2 = 6 + -9

Combine like terms: 9 + -9 = 0
0 + -1a2 = 6 + -9
-1a2 = 6 + -9

Combine like terms: 6 + -9 = -3
-1a2 = -3

Divide each side by '-1'.
a2 = 3

Simplifying
a2 = 3

Take the square root of each side:
a = {-1.732050808, 1.732050808}