Now there are four different integers a, B, C and D whose product ABCD = 25, then a + B + C + D =?

Now there are four different integers a, B, C and D whose product ABCD = 25, then a + B + C + D =?

a+b+c+d=0
a= -1 b=1 c= -5 d=5

This paper proves that (a 2 + B 2) (C 2 + D 2) ≥ (AC + BD) 2, and points out the conditions of the equal sign
Two is square

It is proved that: (AD BC) & sup2; ≥ 0, namely a & sup2; D & sup2; + B & sup2; C & sup2; - 2abcd ≥ 0, namely a & sup2; D & sup2; + B & sup2; C & sup2; ≥ 2abcd, thus (A & sup2; C & sup2; + B & sup2; D & sup2;) + (A & sup2; D & sup2; + B & sup2; C & sup2;) ≥ (A & sup2; C & sup2; + B & sup;)

A3 = a1 + A2, I want to get B3 = B1 + B2, C3 = C1 + C2, D3 = D1 + D2. I use horizontal drag, but B3, C3, D3 copy the value of A3
Why can't I get the number I want? I copy the number of A1

According to your description, it should be set to manual recalculation
Tools - Options - recalculate, select auto recalculate