3+x(.5x)=140

Solution for 3+x(.5x)=140 equation:

Simplifying
3 + x(0.5x) = 140

Remove parenthesis around (0.5x)
3 + x * 0.5x = 140

Reorder the terms for easier multiplication:
3 + 0.5x * x = 140

Multiply x * x
3 + 0.5x2 = 140

Solving
3 + 0.5x2 = 140

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + 0.5x2 = 140 + -3

Combine like terms: 3 + -3 = 0
0 + 0.5x2 = 140 + -3
0.5x2 = 140 + -3

Combine like terms: 140 + -3 = 137
0.5x2 = 137

Divide each side by '0.5'.
x2 = 274

Simplifying
x2 = 274

Take the square root of each side:
x = {-16.552945357, 16.552945357}