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# Solving Quadratic Equation with One Unknown

The quadratic equation can be expressed as

a x2 + b x + c = 0                      (1)

which can be solved for the two alternatives of x as

x1,2 = (-b ± (b2 - 4 a c)1/2) / (2 a)             (2)

### Example - Solving Quadratic Equation

If

a = 1

b = 6

c = 5

then the two alternatives for x can be calculated as

x1 = (-6 + (62 - 4 1 5)1/2) / (2 1)

= -1

x2 = (-6 - (62 - 4 1 5)1/2) / (2 1)

= -5

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## SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!