Ответ:
1200.
Объяснение:
1. d = a3 - a2 = 9-(-3) = 9+3 = 12.
2. a1 = a2 - d = -3 -12 = -15.
3. S16 = (2a1 + 15d)/2•16 = (2a1 + 15d)•8 = (2•(-15) +15•12) •8 = 150•8 = 1200.
d=a3-a2 => d= 9+3=12
a1=a2-d => a1= -3-12=-15
S16= (2×(-15)+12×(16-1))/2×15= 1200
Оtvet: 1200
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Answers & Comments
Ответ:
1200.
Объяснение:
1. d = a3 - a2 = 9-(-3) = 9+3 = 12.
2. a1 = a2 - d = -3 -12 = -15.
3. S16 = (2a1 + 15d)/2•16 = (2a1 + 15d)•8 = (2•(-15) +15•12) •8 = 150•8 = 1200.
d=a3-a2 => d= 9+3=12
a1=a2-d => a1= -3-12=-15
S16= (2×(-15)+12×(16-1))/2×15= 1200
Оtvet: 1200