Question

please solve it.........​

Answer 1

Step-by-step explanation:

I write only here conditions

1) a + (a+d) + (a+2d) +(a+3d) = 20

2)

$a {}^{2} + (a + d) {}^{2} + (a + 2d) {}^{2} +( a + 3d) {}^{2} = 120$

Answer 2

Answer:

see the attachment for the solution