**Please Help, ASAP** Rearrange the formula so the letter in parenthesis is the subject.
1) x+xy = y, (x)
2) x+y = xy, (x)
3) x = y+xy, (x)
4) E = (1/2)mv^2-(1/2)mu^2, (u)
5) (x^2/a^2)-(y^2/b^2) = 1, (y)
6) ay^2 = x^3, (y)

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3