1 . ( 3 - 2х ) ( 8х + 1 ) + ( 4х - 1 )² = 2 . ( 9х + 10 ) ( 9х - 10 ) - ( 7х + 2 )² + 16...

1)
$(3 - 2x)(8x + 1) + (4x - 1) \\ (4x - 1) = \\ = 24x - 16x {}^{2} + 3 - 2x + 16x {}^{2} - \\ - 4x - 4x + 1 = \\ = 14x + 4 = \\ = 2(7x + 2)$

2)
$(9x + 10)(9x - 10) - (7x + 2) \\ (7x + 2) + 16(7 - 2x {}^{2} ) = \\ = 81x {}^{2} - 100 - 49x {}^{2} - 28x - 4 + \\ + 112 - 32x {}^{2} = \\ = 8 - 28x = \\ = 4(2 - 7x)$

3)
$((6x - 1)(6x - 1) - (8x + 1) \\ (8x + 1)) \div ( - 28x) = \\ = (36x {}^{2} - 12x + 1 - 64x {}^{2} - 16x - \\ - 1) \div ( - 28x) = \\ = ( - 28x {}^{2} - 28x) \div ( - 28x) = \\ = ( - 28x {}^{2} - 28x) \times ( - \frac{1}{28} x) = \\ \\ = x {}^{3} + x {}^{2} = \\ = x {}^{2} (x + 1)$

4)
$(4 - x)(4 + x) - (15x {}^{3} - 3x {}^{2} ) \times \\ \times \frac{1}{3 } x {}^{2} + (x + 3)(x + 3) = \\ \\ = 16 - x {}^{2} - 5x {}^{5} + x {}^{4} + x {}^{2} + 6x + \\ + 9 = \\ = 25 - 5x {}^{5} + x {}^{4} + 6x$