(a-b) 2 = a 2-2ab+b 2, (complete square difference)
(a+b) (a-b) = a 2-b 2, (square difference formula)
(x+a)(x+b)=x^2+(a+b)x+ab，
Teacher's Work Summary Personal Summary 1
Over the past year, under the leadership and guidance of my superiors and with the care and help