3=51-2x^2

Solution for 3=51-2x^2 equation:

Simplifying
3 = 51 + -2x2

Solving
3 = 51 + -2x2

Solving for variable 'x'.

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

Add '2x2' to each side of the equation.
3 + 2x2 = 51 + -2x2 + 2x2

Combine like terms: -2x2 + 2x2 = 0
3 + 2x2 = 51 + 0
3 + 2x2 = 51

Add '-3' to each side of the equation.
3 + -3 + 2x2 = 51 + -3

Combine like terms: 3 + -3 = 0
0 + 2x2 = 51 + -3
2x2 = 51 + -3

Combine like terms: 51 + -3 = 48
2x2 = 48

Divide each side by '2'.
x2 = 24

Simplifying
x2 = 24

Take the square root of each side:
x = {-4.898979486, 4.898979486}