Question

с объяснением срочно​.

Answer 1

Ответ:

а) $\left \{ {{x=-\frac{1}{4}-\frac{3}{40}y } \atop {20x-7y=-5}} \right. \\\\20(-\frac{1}{4} -\frac{3}{40} y)-7y=-5\\\\y=0\\\\x=-\frac{1}{4} -\frac{3}{40} *0\\\\x=-\frac{1}{4} \\\\(x,y)=(-\frac{1}{4} ,0)$

б) $\left \{ {{x=\frac{1}{5}-\frac{2}{5}y } \atop {15x+3y=3}} \right.\\\\15(\frac{1}{5} -\frac{2}{5} y)+3y=3\\\\y=0\\\\x=\frac{1}{5} -\frac{2}{5} *0\\\\x=\frac{1}{5}\\\\(x,y)=(\frac{1}{5} ,0)$

в) $\left \{ {{x=\frac{13}{3}-\frac{8}{3}y } \atop {5x-16y=7}} \right. \\\\5(\frac{13}{3} -\frac{8}{3} y)-16y=7\\\\y=\frac{1}{2} \\\\x=\frac{13}{3} -\frac{8}{3} *\frac{1}{2} \\\\x=3\\\\(x,y)=(3,\frac{1}{2} )$

г) $\left \{ {{10x+15y=-45} \atop {x=\frac{33}{2}+\frac{3}{2}y }} \right. \\\\10(\frac{33}{2} +\frac{3}{2} y)+15y=-45\\\\y=-7\\\\x=\frac{33}{2} +\frac{3}{2} *(-7)\\\\x=6\\\\(x,y)=(6, -7)$