`a) x/(x-2y) + x/(x + 2y) + (4xy)/(4y²-x²)`
`=x/(x-2y) + x/(x + 2y) - (4xy)/(x²-4y²)`
`= (x(x+2y))/(x²-4y²) + (x(x-2y))/(x² + 4y²) - (4xy)/(x²-4y²)`
`=(x²+2xy+x²-2y-4xy)/((x+2y).(x-2y))`
`=(2x²-4xy)/((x+2y).(x-2y))`
`=(2x(x-2y))/((x+2y).(x-2y))`
`=(2x)/(x+2y)`
`b) 1/(3x-2) - 1/(3x+2) - (3x-6)/(4-9x²)`
`= 1/(3x-2) - 1/(3x+2) + (3x-6)/(9x²-4)`
`= (3x+2)/(9x²-4) - (3x-2)/(9x²-4) + (3x-6)/(9x²-4)`
`= (3x+2-3x+2+3x-6)/((3x-2).(3x+2)) `
`= (3x-2)/((3x-2).(3x+2)) `
`= 1/(3x+2) `
`c) (x²-36)/(2x+10).(3)/(6-x)`
`= ((x-6).(x+6))/(2x+10).(-3)/(x-6)`
`= (-3(x+6))/(2x+10)`
`= (-3x-18)/(2x+10)`