Group the last three.

4a^2-(b^2+4c^2-4bc)

=4a^2-(b-2c)^2

=(2a+b-2c)(2a-b+2c)

b^2-a^2+2ac-c^2

=b^2-(a-c)^2

=(b+a-c)(b-a+c)

definition

Addition: the operation of combining two numbers into one number.

Subtraction: when two addends and one of them are known, the operation of finding the other addend.

Multiplication: the operation of finding the product of two numbers.

Division: the operation of finding another factor by knowing the product of two factors and one of them.