3x^2y-2xy^2+xy-3x^2y+xy^2+3xy=2xy^2+xy^2+3xy
Х:(а/b)=хb/а
от 20символов
Не забываем одз:
![\left \{ {{1-3x \geq 0} \atop {x+3 \geq 0}} \right. \\ \left \{ {{3x \leq 1} \atop {x \geq -3}} \right. \\ \left \{ {{x \leq \frac{1}{3} } \atop {x \geq -3}} \right. \\ x \in [-3; \frac{1}{3}]](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B1-3x+%5Cgeq+0%7D+%5Catop+%7Bx%2B3+%5Cgeq+0%7D%7D+%5Cright.+%0A%5C%5C+%5Cleft+%5C%7B+%7B%7B3x+%5Cleq+1%7D+%5Catop+%7Bx+%5Cgeq+-3%7D%7D+%5Cright.+%0A%5C%5C+%5Cleft+%5C%7B+%7B%7Bx+%5Cleq++%5Cfrac%7B1%7D%7B3%7D+%7D+%5Catop+%7Bx+%5Cgeq+-3%7D%7D+%5Cright.+%0A%5C%5C+x+%5Cin+%5B-3%3B+%5Cfrac%7B1%7D%7B3%7D%5D+)
теперь можно возвести обе части в квадрат:
![1-3x=x^2+6x+9 \\x^2+9x+8=0 \\D=81-32=49=7^2 \\x_1= \frac{-9+7}{2} =-1 \in [-3; \frac{1}{3}] \\x_2= \frac{-9-7}{2} =-8 \notin [-3; \frac{1}{3}]](https://tex.z-dn.net/?f=1-3x%3Dx%5E2%2B6x%2B9%0A%5C%5Cx%5E2%2B9x%2B8%3D0%0A%5C%5CD%3D81-32%3D49%3D7%5E2%0A%5C%5Cx_1%3D+%5Cfrac%7B-9%2B7%7D%7B2%7D+%3D-1+%5Cin+%5B-3%3B+%5Cfrac%7B1%7D%7B3%7D%5D%0A%5C%5Cx_2%3D+%5Cfrac%7B-9-7%7D%7B2%7D+%3D-8+%5Cnotin+%5B-3%3B+%5Cfrac%7B1%7D%7B3%7D%5D+)
Ответ: x=-1
Фотку открой и посмотри там все написано
Ответ:
Объяснение: делаем формулу: МК=х, МЕ=х+0.6;
х+(0.6+х)=9 2х=9-0.6 х=4.2.
МК=4,2 см, МЕ=4.8