Помогите пж. 2, 4, 6.​

Question

Помогите пж. 2, 4, 6.​

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Answer 1

(10cx-6)(10cx+6) = 100c2x2-36

(1+3ab)(1-3ab) = 1-9a2b2

(0,2t-0,5u)(0,2t+0,5u) = 0,04t2-0.25u2