`b) (3sqrta - 2a - 1)/(4a - 4sqrta + 1) (a >= 0, a ne 1/4)`
`= (-2a + 3sqrta - 1)/(2sqrta. 2sqrta - 2. 2sqrta + 1^2)`
`= (-2sqrta. sqrta + 2sqrta + sqrta - 1)/((2sqrta)^2 - 2. 2sqrta. 1 + 1^2)`
`= (-2sqrta(sqrta - 1) + (sqrta - 1))/(2sqrta - 1)^2`
`= ((-2sqrta + 1)(sqrta - 1))/(2sqrta - 1)^2`
`= (-(2sqrta - 1)(sqrta - 1))/(2sqrta - 1)^2`
`= (-(sqrta - 1))/(2sqrta - 1)`
`= - (sqrta - 1)/(2sqrta - 1)`
`c) (xsqrty - ysqrtx)/(x - 2sqrt{xy} + y) (x, y >= 0, x ne y)`
`= (sqrt{x. x}sqrty - sqrt{y. y}sqrtx)/((sqrtx)^2 - 2sqrtxsqrty + (sqrty)^2)`
`= (sqrt{xy}sqrtx - sqrt{yx}sqrty)/(sqrtx - sqrty)^2`
`= (sqrt{xy}(sqrtx - sqrty))/(sqrtx - sqrty)^2`
`= (sqrt{xy})/(sqrtx - sqrty)`
