Question

25 баллов!!!решить систему уравнений : 2x+3y/4+3x-2y/5=-1/20
3x+4y/2-5x-y/3=43/6

Answer 1

$\begin{cases}\frac{2x + 3y}{4} +\frac{3x-2y}{5}=-\frac{1}{20}\ \ /*20 \\\frac{3x + 4y}{2}-\frac{ 5x-y}{3} = \frac{43}{6}\ \ /*6\end{cases}\\\\\begin{cases} 5(2x + 3y)+ 4(3x-2y) =-1\\ 3(3x + 4y)-2(5x-y )=43\end{cases}\\\\\begin{cases} 10x + 15y + 12x-8y =-1\\ 9x + 12y -10x+2y=43\end{cases} \\\\\begin{cases} 22x + 7y =-1\ \ /*(-2)\\ -x+14y =43 \end{cases} \\\\\begin{cases} -44x -14y =2\\ - x+14y =43 \end{cases}\\+--------\\ -45x=45\ \ /:(-45)$

$x=-1\\\\22x+7y=-1\\22*(-1)+7y=-1\\-22+7y=-1\\7y=-1+22\\7y=21\ \ /:7\\y=3\\\\\begin{cases} x=-1 \\ y=3 \end{cases}$