Question

Care stie cum se rezolva 2)c?

Answer 1

Răspuns:

Explicație pas cu pas:

arati mai intai , pas cu pas,  folosind punctul a),care, rezolvat sau nu, acum face parte din IPOTEZA (date)  

ca

x°x°x°x=(x-3)^4+3

atunci

(x-3)^4=16

x-3= +- rad ord 4 din 16=+-2

x-3=-2.....x=1

x-3=2........x=5

S= {1;5}

Answer 2

$\displaystyle x*y=xy-3x-3x+12\\ \\ x*y=xy-3x-3y+9+3=x(y-3)-3(y-3)+3=\\ \\ =(x-3)(y-3)+3\\ \\ x*x*x*x=19 \\ \\ x*x=(x-3)(x-3)+3=(x-3)^2+3\\ \\ x*x*x=((x-3)^2+3-3)(x-3)+3=(x-3)^2(x-3)+3=\\ \\ =(x-3)^3+3\\ \\ x*x*x*x=((x-3)^3+3-3)(x-3)+3=(x-3)^3(x-3)+3=\\ \\ =(x-3)^4+3\\ \\ x*x*x*x=19 \Rightarrow (x-3)^4+3=19 \\ \\ (x-3)^4=19-3 \\ \\ (x-3)^4=16 \\ \\ x-3=-\sqrt[4]{16} \Rightarrow x-3=-\sqrt[4]{2^4}\Rightarrow x-3=-2 \Rightarrow x=-2+3\Rightarrow x=1$

$x-3=\sqrt[4]{16} \Rightarrow x-3=\sqrt[4]{2^4} \Rightarrow x-3=2\Rightarrow x=2+3\Rightarrow x=5 \\ \\ S=\{1;5\}$