Question

40 баллов! решить с объяснением​

Answer 1

$\left \{ {{a_{1}+a_{5} =28} \atop {a_{2}+a_{3}=24}} \right.\\\\\left \{ {{a_{1}+a_{1}+4d=28} \atop {a_{1}+d+a_{1}+2d=24 }} \right.\\\\-\left \{ {{2a_{1}+4d=28 } \atop {2a_{1}+3d=24 }} \right.\\ -------\\\boxed{d=4}$