a = (3x + 4) (x + 2) + (5x + 1) (x - 2)
a = 3x² + 6x + 4x + 8 + 5x² - 10x + x - 2
a = 3x² + 5x² + 6x + 4x + x - 10 + 8 - 2
a = 8x² + x + 6
b = (2x + 5) (- x + 2) - (x - 3) (- 3x + 4)
b = - 2x² + 4x - 5x + 10 - (- 3x² + 4x + 9x - 12)
b = - 2x² + 4x - 5x + 10 + 3x² - 4x - 9x + 12
b = - 2x² + 3x² + 4x - 4x - 5x - 9x + 10 + 12
b = x² - 14x + 22
c = (x - 8)²
c = x² - 16x + 64
d = (5x + 3)²
d = 25x²+ 30x + 9
e = (4x + 9) (4x - 9)
e = 16x² - 36x + 36x - 81
e = 16x² - 81