Question

9 Efectuati produsele:
a) (x+1)(x+2)
10 Calculati:
a) 3(x+2y)-5(3x-3y)+7(3x-5y)
11 Efectuati calculele:
a) 2x•0,5y-0,3x•5y+1,25x•y+0,5x•0,5y
12 Efectuati:
a) (x-3)(x+2)+(2x+1)(3x-2)-2x(x+1)
13 Efectuati:
a) 3√5•(√5a)+9a:(-3)-√7:√7/4a, a≠0
14 Efectuati
a) (3x+1)(x²+2x-5)-(x+2)(2x²-x+3)
15 Consideram numarul N=(a+1)(b+2)
a) Calculati N daca a=2 si b=3

Answer 1

a) (x+1)(x+2)=x²+x+2x+2=x²+3x+2

a) 3(x+2y)-5(3x-3y)+7(3x-5y)=
=3x+6y-15x+15y+21x-35y=
=9x-14y

a) 2x•0,5y-0,3x•5y+1,25x•y+0,5x•0,5y=
= xy-1,5xy+1,25xy+0,25xy=
= xy

a) (x-3)(x+2)+(2x+1)(3x-2)-2x(x+1)=
= x²-3x+2x-6+6x²+3x-4x-2-2x²-2x=
= 5x²-4x-8

a) 3√5•(√5a)+9a:(-3)-√7:√7/4a, a≠0
=15a-3a-4a=8a

a) (3x+1)(x²+2x-5)-(x+2)(2x²-x+3)=
= 3x³+x²+6x²+2x-15x-5-2x³-4x²+x²+2x-3x-6=
= x³+4x²-14x-11


15 Consideram numarul N=(a+1)(b+2)
a) Calculati N daca a=2 si b=3
N=(2+1)(3+2)=3×5=15