2a^2-a-1=2

Solution for 2a^2-a-1=2 equation:

Simplifying
2a2 + -1a + -1 = 2

Reorder the terms:
-1 + -1a + 2a2 = 2

Solving
-1 + -1a + 2a2 = 2

Solving for variable 'a'.

Reorder the terms:
-1 + -2 + -1a + 2a2 = 2 + -2

Combine like terms: -1 + -2 = -3
-3 + -1a + 2a2 = 2 + -2

Combine like terms: 2 + -2 = 0
-3 + -1a + 2a2 = 0

Factor a trinomial.
(-1 + -1a)(3 + -2a) = 0

Subproblem 1
Set the factor '(-1 + -1a)' equal to zero and attempt to solve:

Simplifying
-1 + -1a = 0

Solving
-1 + -1a = 0

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

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

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

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

Divide each side by '-1'.
a = -1

Simplifying
a = -1
Subproblem 2
Set the factor '(3 + -2a)' equal to zero and attempt to solve:

Simplifying
3 + -2a = 0

Solving
3 + -2a = 0

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

Add '-3' to each side of the equation.
3 + -3 + -2a = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -2a = 0 + -3
-2a = 0 + -3

Combine like terms: 0 + -3 = -3
-2a = -3

Divide each side by '-2'.
a = 1.5

Simplifying
a = 1.5
Solution
a = {-1, 1.5}