Question

Am nevoie de ajutor la punctul f)

Answer 1

f) (2x + 1)² - 3(x + 3)(x - 2) - (x+ 1)(x - 8)=
=2x² + 4x + 1 - 3(x² - 2x + 3x -6) - (x² - 8x + x - 8)=
=2x² + 4x + 1 - 3x² + 6x - 9x + 18 - x² + 8x - x + 8=
=2x² - 3x² - x² + 4x + 6x - 9x + 8x - x + 1 +18 +8=
= - 2x² + 8x + 27

Answer 2

f) (2x+1)² - 3(x+3)(x-2) - (x+1)(x-8) 

Folosim formula de calcul prescurtat: (a+b)² = a² + 2ab + b²

= 4x² + 4x + 1 + ( - 3x - 9 )(x+2) - ( x² -8x+x-8) = 

Se inmultesc parantezele

= 4x² + 4x + 1 - 3x² + 6x - 9x + 18 - x² + 7x + 8 =

Se reduc termenii asemenea

= 0 + 4x + 1 + 6x - 9x + 18 + 7x + 8 =

= 0 + 8x + 1 + 18 + 8 =

= 0 + 8x + 27 = 8x+27