Question

Помогите срочно !!! (5c-1)(5c+1)
(3а+2b)(3а-b)

Answer 1

(5c-1)(5c+1)=(5с)^2-1^2=25c^2-1
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(3а+2b)(3а-b)=9a^2-3ab+6ab-2b^2=9a^2+3ab-2b^2