Question

С1. как решить 7^(x^2-2x)+7^(x^2-2x-1)=56 

Answer 1

7^(x²-2x-1)*(7+1)=56
7^(x²-2x-1)*8=56
7^(x²-2x-1)=7
x²-2x-1=1
x²-2x-2=0
D=4+8=12
x1=(2-2√3)/2=1-√3
x2=1+√3

Answer 2

$7^{x^2-2x}+7^{x^2-2x-1}=56 textless = textgreater 7^{x^2-2x-1}(7+1)=56to\7^{x^2-2x-1}=frac{56}{8}=7^1to x^2-2x-1=1\x^2-2x-2=0\D=sqrt{(-2)^2-4*1*(-2)}=sqrt{4(1-(-2))}=sqrt{12}=sqrt{4*3}\x_{1,2}=frac{-bб2sqrt{3}}{2*1}=frac{2(1бsqrt{3})}{2}=1бsqrt{3}to \x_1=1+sqrt{3}\x_2=1-sqrt{3}$