Răspuns:
Explicație pas cu pas:
a ) E(x) = (X+2)²+ ( X - 2)·( X + 2 )
E(x) = x²+4x+4 + x²-4 = 2x²+4x = 2x(x+2)
b) E(x) = (X-3) ·(X+3) - (X-4)² = x²-9 - (x²-8x+16) =
= x²-9-x²+8x-16 = 8x-25
c) E(X) = ( 2X -5)²+(X +1 ) - (X√5 +3 ) ·(X√5 - 3 )
E(x) = 4x²-20x+25+x+1- 5x²+9 = -x²-19x+35
d) E(X) =2(X - 6 )² + (X - 2√3 ) ·(X+2√3 ) - ( 2X - 1 )²
E(x) = 2(x²-12x+36) + x²-12 - (4x²-4x+1) =
= 2x²-24x+72+x²-12-4x²+4x-1 = -x²-20x+59
#copaceibrainly