S15 = ((2*(-20)+12*14)/2)*15
S15 = -40+168 = 128/2=64*15=960
Ответ: 960
(7х-49)(12-2х)=0
-14x^2+182x-588=0
-14×(x^2-13x+42)=0
x^2-13+42=0
D=b^2-4ac=(-13)^2-4×(1×42)=1
x=6
x=7
(3a⁻⁶)⁴ *a⁴⁵=3⁴ *a⁻⁶*⁴ *a⁴⁵=81a⁻²⁴⁺⁴⁵=81a²¹
Ответ:
Объяснение:
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1) 5a – 3b – 8a + 12b = –3a + b
2) 16c + (3c – 2) – (5c +7) = 16c + 3c - 2 - 5c - 7 = 14c - 9
3) 7 - 3(6y - 4) = 7 - 17y + 12 = -17y + 19