Решите пожалуйста прошу спасибо заранее

Решите задачу:

$1) \left \{ {{x+y=-4} \atop {3x-y=16}} \right. \\ x+y+3x-y=-4+16 \\ 4x=12 \\ x=3 \\ y=-4-x \\ y=-4-3=-7$
$2) \left \{ {{5x-7y=-11} \atop {3x+7y=27}} \right. \\ 5x-7y+3x+7y=-11+27 \\ 8x=16 \\ x=2 \\ y= \frac{27-3x}{7}= \frac{27-6}{7}=3$
$3) \left \{ {{2x-y=7} \atop {2x+3y=27}} \right. \\ 2x-y-2x-3y=7-27 \\ -4y=-20 \\ y=5 \\ x= \frac{7+y}{2}= \frac{7+5}{2} =6$
$4) \left \{ {{3x+y=8} \atop {4x-2y=-6}} \right. \\ \left \{ {{3x+y=8} \atop {2x-y=-3}} \right. \\ 3x+y+2x-y=8-3 \\ 5x=5 \\ x=1 \\ y=8-3x=8-3=5$
$5) \left \{ {{5x-7y=-64} \atop {8x+4y=4}} \right. \left \{ {{5x-7y=-64} \atop {2x+y=1}} \right. \\ y=1-2x \\ 5x-7(1-2x)=-64 \\ 5x-7+14x=-64 \\ 19x=-57 \\ x=-3 \\ y=1-2*(-3)=7$
$6) \left \{ {{x-y=12} \atop {5x+y=48}} \right. \\ x-y+5x+y=12+48 \\ 6x=60 \\ x=10 \\ y=x-12 \\ y=10-12=-2$