Question

Buna imi puteti arata cu se fac aceste exercitii cu calcul prescurtat
 ?






1.(x-2)(x+2)(x²+4)-(x²+1)²+2(x+1)²

2.(√5+1)²-√5(2√5+2)

Answer 1

1.(x-2)(x+2)(x² +4)-( x²+1)+2(x+1)²
<=> (x²-4)(x²+4)-(x^4+2x²+1)+2(x²+2x +1)
<=>(X^4-16)-(X^4+2x²+1)+2x²+4x+2
<=>x^4-16-x^4+2x²+1+2x²+4x+2
<=>4x²+4x+3-16
<=>4x²+4x-13

2. (√5+1)²-√5(2√5+2)
<=>(5+2√5+1)-2*5+2√5
<=>5+2√5+1-10+2√5
<=>6-10+4√5
<=> 4√5-4

P.S. x^4 inseamna x la puterea 4