164=6a^2-4(a^2+9)

Solution for 164=6a^2-4(a^2+9) equation:

Simplifying
164 = 6a2 + -4(a2 + 9)

Reorder the terms:
164 = 6a2 + -4(9 + a2)
164 = 6a2 + (9 * -4 + a2 * -4)
164 = 6a2 + (-36 + -4a2)

Reorder the terms:
164 = -36 + 6a2 + -4a2

Combine like terms: 6a2 + -4a2 = 2a2
164 = -36 + 2a2

Solving
164 = -36 + 2a2

Solving for variable 'a'.

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

Add '-2a2' to each side of the equation.
164 + -2a2 = -36 + 2a2 + -2a2

Combine like terms: 2a2 + -2a2 = 0
164 + -2a2 = -36 + 0
164 + -2a2 = -36

Add '-164' to each side of the equation.
164 + -164 + -2a2 = -36 + -164

Combine like terms: 164 + -164 = 0
0 + -2a2 = -36 + -164
-2a2 = -36 + -164

Combine like terms: -36 + -164 = -200
-2a2 = -200

Divide each side by '-2'.
a2 = 100

Simplifying
a2 = 100

Take the square root of each side:
a = {-10, 10}