Răspuns:
Explicație pas cu pas:
1)
a)
(x+4)²=x²+2x*4+4²= X²+8x+16
b)
(3x-1)²=(3x)²-2*3x *1 +1²= 9x²-6x+1
2)
(2x-5)²+3(x-2)( x+2)-( x+4)²=[( 2x)²-2*2x*5 +5²]+3*(x²-2²)- [(x)²+2x*4 +4²] = (4x²-20x+25) +3( x²-4) -(x²+3x+16) = 4x²-20x +25+3x²-3*4-8x-16)= 4 x²-20x +25 +3x²-12-x²-8x-16= 6x²-28x-3
3)
x+y=5
x²-y²=15
x²-y²=(x-y) (x+y)
5( x-y) =15
= se imparte cu 5
x-y=3
a= (x-y)+(x-y)²-(x-y)³
a= 3+3²-3³
a= 3+3-27
a= 12-27
a= -15
