а)2a^2 - 2b^2 - a + b = 2(a^2-b^2) - (a-b) = 2(a+b)(a-b) - (a-b) = (2a+2b-1)(a-b)
б)81x^2 - (5x-1)^2 = (9x)^2 - (5x-1)^2 = (9x + 5x - 1)(9x - 5x + 1) = (14x - 1)(4x + 1)
а)
2a^2 - 2b^2 - a + b = 2(a^2-b^2) - (a-b) = 2(a+b)(a-b) - (a-b) = (2a+2b-1)(a-b)
б)
81x^2 - (5x-1)^2 = (9x)^2 - (5x-1)^2 = (9x + 5x - 1)(9x - 5x + 1) = (14x - 1)(4x + 1)