Fill in the blanks to make the statements true:

a² – b² = (a + b) …………… .

Fill in the blanks to make the statements true:

a (b + c) = ax ……….. × ax ……….. .

Fill in the blanks to make the statements true:

(a – b) …………….. = a² – 2ab + b²

Fill in the blanks to make the statements true:

(a – b)² + ……….. = a² – b²

Fill in the blanks to make the statements true:

(a + b)² - 2ab = ……… + ……… .