30.0=0.5*70.0*x^2

Solution for 30.0=0.5*70.0*x^2 equation:

Simplifying
30.0 = 0.5 * 70.0x2

Multiply 0.5 * 70.0
30.0 = 35x2

Solving
30.0 = 35x2

Solving for variable 'x'.

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

Add '-35x2' to each side of the equation.
30.0 + -35x2 = 35x2 + -35x2

Combine like terms: 35x2 + -35x2 = 0
30.0 + -35x2 = 0

Add '-30.0' to each side of the equation.
30.0 + -30.0 + -35x2 = 0 + -30.0

Combine like terms: 30.0 + -30.0 = 0.0
0.0 + -35x2 = 0 + -30.0
-35x2 = 0 + -30.0

Combine like terms: 0 + -30.0 = -30
-35x2 = -30

Divide each side by '-35'.
x2 = 0.8571428571

Simplifying
x2 = 0.8571428571

Take the square root of each side:
x = {-0.9258201, 0.9258201}