This is a further modification of the work by Ishak at
https://www.geogebra.org/material/show/id/P4TmVmvT
and also from
https://www.geogebra.org/material/show/id/vTC6b7Y6
The student not only forms the expressions in multiplication frame but also types in the factorized quadratic expression when the frame has the correct expressions.
(Update 3 Dec 2021 : Thanks to Ng Yew Hong's suggestion, I have altered to include
SetValue(f_{c1},undefined)
SetValue(f_{c2},undefined)
SetValue(f_{r1},undefined)
SetValue(f_{r2},undefined)
when resetting new problem.
Also updated minor expressions to make them more readable.
