Răspuns:
E(x)=(3x+1)²-2(x-4)²+(5+x)(5-x)-5x(x+4)+3=
9x²+6x+1-2(x²-8x+16)+25-x²-5x²-20x+3=
9x²+6x+1-2x²+16x-32+25-x²-5x²-20x+3=
x²(9-2-1-5)+x(6+16-20)+1-32+25+3=
x²+2x-3=(x-1)(x+3)
a)E(x)=x²+2x-3
E(x)=(x-1)(x+3)
b)E(2√2-1)=(2√2-1)²+2(2√2-1)-3=
8-4√2+1+4√2-2-3=(8+1-2-3)+(-4√2+4√2)=
4+0=4
