1) а2 + 4а2 - 4ас + с2 = 5а2 - 4ас + с2
2) 25t2 + 70tz + 49z2 - 70tz = 25t2 + 49z2
3) 16b2 - (a2 - 8ab + 16b2) = 16b2 - a2 + 8ab - 16 b2 = -a2 + 8ab
Sin x< - √2/2
(- 3п/4 + 2Пn; - п/4 + 2Пn)
9a^2-6ab+b^2-16
(3-b)^2-16
(3a-b-4)*(3a-b+4)
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