a-3=a^2

Solution for a-3=a^2 equation:

Simplifying
a + -3 = a2

Reorder the terms:
-3 + a = a2

Solving
-3 + a = a2

Solving for variable 'a'.

Combine like terms: a2 + -1a2 = 0
-3 + a + -1a2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
3 + -1a + a2 = 0

Move the constant term to the right:

Add '-3' to each side of the equation.
3 + -1a + -3 + a2 = 0 + -3

Reorder the terms:
3 + -3 + -1a + a2 = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1a + a2 = 0 + -3
-1a + a2 = 0 + -3

Combine like terms: 0 + -3 = -3
-1a + a2 = -3

The a term is a.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
-1a + 0.25 + a2 = -3 + 0.25

Reorder the terms:
0.25 + -1a + a2 = -3 + 0.25

Combine like terms: -3 + 0.25 = -2.75
0.25 + -1a + a2 = -2.75

Factor a perfect square on the left side:
(a + 0.5)(a + 0.5) = -2.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.