Question

Urgent... dau 15 puncte Calculati:

(y-4)^3 =
(7x+a)^3 =
(5a-1)(5a+1) =
(3a+2b)^3 =

Answer 1

Răspuns:

(y-4)^3=y³-3*y²*4+3*y*4²-4³=y³-12y²+48y-64

(7x+a)^3 =(7x)³+3*(7x)²*a+3*7x*a²+a³=343x³+147x²a+21xa²+a³

(5a-1)(5a+1) =5a²-1²=25a²-1

(3a+2b)^3=(3a)³+3*(3a)²*2b+3*3a*(2b)²+

(2b)³=27a³+54a²b+36ab²+8b³

FORMULELE:

(a+b)³=a³+3*a²*b+3*a*b²+b³

(a-b)³=a³-3*a²*b+3*a*b²-b³

(a+b)(a-b)=a²-b2