Question

Thu gọn các biểu thức sau:

A=(x-1)^3-x(x-2)^2+1

B=(-x-2)^3+(2x-4)(x^2+2x+4)- x^2(x-6)

Answer 1

A = (x - 1)³ - x(x - 2)² + 1

A = (x - 1)(x² - 2x + 1) - x(x - 2)² + 1

A = x(x² - 2x + 1) - (x² - 2x + 1) - x(x - 2)² + 1

A = x³ - 2x² + x - (x² - 2x + 1) - x(x² - 2x.2 + 2²) + 1

A = x³ - 2x² + x - (x² - 2x + 1) - (x³ - 4x² + 4x) + 1

A = x³ - 2x² + x - x² + 2x - 1 - x³ + 4x² - 4x + 1

A = (x³ - x³) + (-2x² - x² + 4x²) + (x + 2x - 4x) + (-1 + 1)

A = x² - x

B = (-x - 2)³ + (2x - 4)(x² + 2x + 4) - x²(x - 6)

B = (-x - 2)[(-x²) - 2.(-x).2 + 2²] + (2x - 4)(x² + 2x + 4) - x²(x - 6)

B = -x[(-x)² - 2.(-x).2 + 2²] - 2[(-x)² - 2.(-x).2 + 2²] + (2x - 4)(x² + 2x + 4) - x²(x - 6)

B = -(x³ + 4x² + 4x) - (2x² + 4x + 8) + 2x(x² + 2x + 4) - 4(x² + 2x + 4) - x²(x - 6)

B = -(x³ + 4x² - 4x) - (2x² + 4x + 8) + 2x³ + 4x² + 8x - (x² + 8x + 16) - (x³ - 6x²)

B = -x³ - 4x² + 4x - 2x² - 4x - 8 + 2x³ + 4x² + 8x - x² - 8x - 16 - x³ + 6x²

B = (-x³ + 2x³ - x³) + (-4x² - 2x² + 4x² - x² + 6x²) + (-4x - 8x + 8x - 8x) + (-8 - 16)

B = -12x - 24