`a)`
`2/(15x^3y^2) = (2.2.x.y)/(30x^4y^3) = (4xy)/(30x^4y^3)`
`y/(10x^4y^3) = (y.3)/(30x^4y^3) = (3y)/(30x^4y^3)`
`c)`
`(7x-1)/(2x^2+6x) = (7x-1)/(2x(x+3)) = ((7x-1)(x-3))/(2x(x+3)(x-3))`
`(3-2x)/(x^2-9) = (3-2x)/((x-3)(x+3)) = (2x(3-2x))/(2x(x+3)(x-3))`