I can't see the instructions, so I assume you're solving for the variable to the right.
(a) A = pi*r(l+L), first divide both sides pi*r A/(pi*r) = l + L, next subtract l from both sides L = A/(pi*r) - l
(b) V = pi*r^2*h, first isolate the variable r by dividing both sides by pi*h V/(pi*h) = r^2, next take the inverse operation of square, which is the square root r = sqrt root [ V/(pi*h)], assume r is a positive number only, so you do not need to consider the - square root option
(d) t = 2*pi*sqrt (L/g), first divide both sides by 2*pi to isolate the radical t/(2*pi) = sqrt (L/g), next square both sides to remove the radical sign over L [t/(2*pi)]^2 = L/g, last multiply both sides by g L = g*[t/(2*pi)]^2
(e) (actually it should say KE for kinetic energy) E = (1/2)mv^2, multiply both sides by 2 and divide both sides by m 2*E/m = v^2, next take the inverse operation of square, square root of both sides v = sqrt [2*E/m], again assume v is a positive quantity, although velocity is a vector quantity and should indicate both magnitude and direction
