Explicație pas cu pas:
a) x(-2x + 1) + 3x(x - 2)
= - 2x^2 + x + 3x^2 - 6x
= x^2 - 5x
b) (2x + 3)(x - 1) + (3x - 2)(-x + 5)
=2x^2 - 2x + 3x - 3 - 3x^2 + 15x + 2x - 10
= - x^2 + 18x - 13
c) (-5x + 2)(3x - 1) + (15x + 7)(x - 3)
= - 15x^2 + 5x + 6x - 2 + 15x^2 - 45x +7x - 21
= - 27x - 23
d) (x - 1)(-5x + 3) + 5x(x - 1)
= - 5x^2 + 3x + 5x - 3 + 5x^2 - 5x
= 3x - 3
e) (x + 2)(x^2 - 2x + 4) - x^3 + 8
= x^3 - 2x^2 + 4x + 2x^2 - 4x +8 - x^3 +8
= 16
f) (2x - 1)(4x^2 + 2x + 1) + 1 - 8x^3
= 8x^3 + 4x^2 + 2x - 4x^2 - 2x - 1 + 1 - 8x^3
= 0
