Đáp án+Giải thích các bước giải:
e, -3x(x + 2)² + (x + 3)(x - 1)(x + 1) - (2x - 3)²
= -3x .(x² + 4x + 4) + (x + 3).(x² - 1) - (4x² - 12x + 9)
= -3x³ - 12x² - 12x + x³ - x + 3x² - 3 - 4x² + 12x - 9
= -2x² - 13x² - x - 12
f, (x - 3)(x + 3)(x + 2) - (x - 1)(x² - 3) - 5x(x + 4)² - (x - 5)²
= (x² - 9)(x + 2) - (x³ - 3x - x² + 3) - 5x(x² + 8x + 16) - (x² - 10x + 25)
= x³ + 2x² - 9x - 18 - x³ + 3x + x² - 3 - 5x³ - 40x² - 80x - x² + 10x - 25
= -5x³ - 38x² - 76x - 46
g, (3x - 2)(5x + 4) - (2x + 7)(4x - 1) + 1
= 15x² + 12x - 10x - 8 - 8x² + 2x - 28x + 7 + 1
= 7x² - 24x
h, (2x + 1)² + (3x - 2)² + (4 + 5x)(4 - 5x)
= 4x² + 4x + 1 + 9x² - 12x + 4 + 16 - 25x²
= -12x² - 8x + 21
i, (2x - 1)(4x² + 2x + 1) + (3 + 2x)(9 - 6x + 4x²) - 7
= 8x³ - 1 + 27 - 8x³ - 7
= 19
