Factorizing Quadratic Polynomials 因式分解

Factorize the randomly-given quadratic polynomials

in the form of ax²+bx+c.

因式分解一元二次多項式ax²+bx+c。

For level 1, a=1; for level 2, a=1,2,3,5,7; for level 3, a=1,2,3,..,12.

程度1，a=1；程度2，a=1,2,3,5,7；程度3，a=1,2,3,..,12。

http://www.geogebratube.org/material/show/id/12136 (Download GeoGebra file)