`(x-5)^2 - (x+5)^2`
`= [(x-5)-(x+5)].[(x-5)+(x+5)]`
`= (x-5-x-5)(x-5+x+5)`
`= -10.2x`
`= -20x`
`(6x+1)(1-6x) + 36x^2 - 5`
`= 1^2 - (6x)^2 + 36x^2 - 5`
`= 1 - 36x^2 + 36x^2 - 5`
`= 1 - 5`
`= -4`
`#3107.101107`
`2.`
`a)`
`(x - 5)^2 - (x + 5)^2`
`= (x - 5 - x - 5)(x - 5 + x + 5)`
`= -10 * 2x`
`= -20x`
`b)`
\(\left(6x+1\right)\left(1-6x\right)+36x^2-5\)
`= -(6x + 1)(6x - 1) + 36x^2 - 5`
`= -(36x^2 - 1) + 36x^2 - 5`
`= -36x^2 + 1 + 36x^2 - 5`
`= -4`