2.57=7x*x

Solution for 2.57=7x*x equation:

Simplifying
2.57 = 7x * x

Multiply x * x
2.57 = 7x2

Solving
2.57 = 7x2

Solving for variable 'x'.

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

Add '-7x2' to each side of the equation.
2.57 + -7x2 = 7x2 + -7x2

Combine like terms: 7x2 + -7x2 = 0
2.57 + -7x2 = 0

Add '-2.57' to each side of the equation.
2.57 + -2.57 + -7x2 = 0 + -2.57

Combine like terms: 2.57 + -2.57 = 0.00
0.00 + -7x2 = 0 + -2.57
-7x2 = 0 + -2.57

Combine like terms: 0 + -2.57 = -2.57
-7x2 = -2.57

Divide each side by '-7'.
x2 = 0.3671428571

Simplifying
x2 = 0.3671428571

Take the square root of each side:
x = {-0.605923145, 0.605923145}