Question

Буду очень благодарна!

Answer 1

$A(1;2) ; ,; B(-1;2); ,; C(3;0)\\1)quad AB=sqrt{(-1-1)^2+(2-2)^2}=2$

$AC=sqrt{(3-1)^2+(0-2)^2}=sqrt{4+4}=2sqrt2\\BC=sqrt{(3+1)^2+(0-2)^2}=sqrt{16+4}=sqrt{20}=2sqrt5\\P=AB+AC+BC=2+2sqrt2+2sqrt5=2(1+sqrt2+sqrt5)$

$2)quad AB:; ; y_{A}=y_{B}; ; ; to ; ; underline {y=2}\\BC:; ; frac{x-x_{B}}{x_{C}-x_{B}} = frac{y-y_{B}}{y_{C}-y_{B}} \\ frac{x+1}{3+1} = frac{y-2}{0-2} ; ,; ; frac{x+1}{4} = frac{y-2}{-2} ; ; to ; ; -2(x+1)=4(y-2); |:(-2)\\x+1=-2(y-2)\\x+1=-2y+4\\x+2y-3=0\\2y=-x+3\\underline {y=-0,5x+1,5}$