P = [(2x + 1)/(x√x - 1) - (√x)/(x + √x + 1)].[(1 + √x^3)/(1 + √x) - (x)] √= [(2x + 1)/(√x^3 - 1) - (√x)/(x + √x + 1)].{[(1 + √x)(x - √x + 1)]/(1 + √x) - √x] = {(2x + 1)/[(√x - 1)(x + √x + 1)] - [(√x).(√x - 1)]/[(√x - 1)(x + √x + 1)]}{x - √x + 1 - √x} = {(x + 1 + √x)/[(x - 1)(x + √x + 1)]}[x - 2√x + 1] = [1/(x - 1)][(√x - 1)^2] = √x - 1 b) P = √x - 1 = 3 < = >√x - 1 = 3 < = >√x = 4 < = >x = 16