Question

Efectuati :
a) (x+y+2) totul la 2 =
b) (X+2y+1) totul la 2 =
c) (2x+y+5) totul la 2=
d) (x+2y+z) totul la 2 =
e ) (3a+2b+1) totul la 2 =
f) (x+y+4)totul la 2=

Answer 1

a) (x+y+2)² =(x+y+2)(x+y+2)=x²+xy+2x+xy+y²+2y+2x+2y+4=x²+y²+2xy+4x+4y+4=(x+y)²+4(x+y+1)
b) (X+2y+1)² =x²+2xy+x+2xy+4y²+2y+x+2y+1=x²+4y²+4xy+2x+4y+1=4y(y+x)+x(x+2)+4y+1
c) (2x+y+5)²=4x²+2xy+10x+2xy+y²+5y+10x+5y+25=4x²+y²+4xy+20x+10y+25=4x(x+y)+y²+5(4x+2y+5)
d) (x+2y+z)² =x²+2xy+xz+2xy+4y²+2yz+xz+2yz+z²=x²+4y²+z²+4xy++2xz+4yz=
x²+4y²+z²+2(2xy+xz+2yz)
e ) (3a+2b+1)² =9a²+6ab+3a+6ab+4b²+2b+3a+2b+1=9a²+4b²+12ab+6a+4b+1
f) (x+y+4)²=x²+xy+4x+xy+y²+4y+4x+4y+16=x²+y²+2xy+8x+8y+16