а7+а3=-8
а8-а5=-6
(а1+6d)+(a1+2d)=-8
(a1+7d)-(a1+4d)=-6
a1+6d+a1+2d=-8
a1+7d-a1-4d=-6
2a1+8d=-8
3d=-6
2a1+8*(-2)=-8
d=-2
a1=4
а7+а3=-8
а8-а5=-6
(а1+6d)+(a1+2d)=-8
(a1+7d)-(a1+4d)=-6
a1+6d+a1+2d=-8
a1+7d-a1-4d=-6
2a1+8d=-8
3d=-6
2a1+8*(-2)=-8
d=-2
a1=4
d=-2