[tex]10x^2+11xy+3y^2=7\\
10x^2+5xy+6xy+3y^2=7\\
5x(2x+y)+3y(2x+y)=7\\
(5x+3y)(2x+y)=7\\\\
\underline{1.\ 5x+3y=1 \wedge 2x+y=7}\\
5x+3y=1\\2x+y=7\\\\
5x+3y=1\\
y=7-2x\\\\
5x+3(7-2x)=1\\
5x+21-6x=1\\
-x=-20\\
x=20\\\\
y=7-2\cdot20=7-40=-33[/tex]
[tex]\underline{2.\ 5x+3y=7 \wedge 2x+y=1}\\
5x+3y=7\\2x+y=1\\\\
5x+3y=7\\
y=1-2x\\\\
5x+3(1-2x)=7\\
5x+3-6x=7\\
-x=4\\
x=-4\\\\
y=1-2\cdot(-4)=1+8=9\\\\
[/tex]
[tex]\underline{3.\ 5x+3y=-1 \wedge 2x+y=-7}\\
5x+3y=-1\\ 2x+y=-7\\\\
5x+3y=-1\\
y=-7-2x\\\\
5x+3(-7-2x)=-1\\
5x-21-6x=-1\\
-x=20\\
x=-20\\\\
y=-7-2\cdot(-20)=-7+40=33[/tex]
[tex]\underline{4.\ 5x+3y=-7 \wedge 2x+y=-1}\\
5x+3y=-7\\
2x+y=-1\\\\
5x+3y=-7\\
y=-1-2x\\\\
5x+3(-1-2x)=-7\\
5x-3-6x=-7\\
-x=-4\\
x=4\\\\
y=-1-2\cdot4=-1-8=-9
[/tex]
[tex]x=20 \wedge y=-33\\x=-4 \wedge y=9\\x=-20 \wedge y=33\\x=4 \wedge y=-9[/tex]
