3.1 Pull out q-4
After pulling out, we are left with :
(q-4) • ( y2 * 1 +( c * (-1) ))
3.2 Factoring: y2-c
Theory : A difference of two perfect squares, A2 - B2 can be factored into (A+B) • (A-B)
Proof : (A+B) • (A-B) =
A2 - AB + BA - B2 =
A2 - AB + AB - B2 =
A2 - B2
Note : AB = BA is the commutative property of multiplication.
Note : - AB + AB equals zero and is therefore eliminated from the expression.
Check : y2 is the square of y1
Check : c1 is not a square !!
Ruling : Binomial can not be factored as the difference of two perfect squares