Question

N=(x+3)²-2x-(2+x)²
Numarul : |3√2-2√5|+2•|1-2√5| este..

Answer 1

$1).N=(x+3)^2-2x-(2+x)^2 \\ N=x^2+2*x*3+3^2-2x-(2^2+2*x*2+x^2) \\ N=x^2+6x+9-2x-(4+4x+x^2) \\ N=x^2+6x+9-2x-4-4x-x^2 \\ N=9-4 \\ N=5 \\ 2).|3 \sqrt{2} -2 \sqrt{5} |+2|1-2 \sqrt{5} |=2 \sqrt{5} -3 \sqrt{2} +2(2 \sqrt{5} -1)= \\ =2 \sqrt{5} -3 \sqrt{2} +4 \sqrt{5} -2=7 \sqrt{5} -3 \sqrt{2} -2$