Help with rearranging formula

Hello, Im looking for some guidance in rearranging formula. Need to ask if what I'm doing is right?

1) 4 (^x+1) = 6 ^0.5x , find x

ln4 (^x+1) = ln6(^0.5x)

x+1(ln4) = 0.5xln6

1.38x +1.38 = 0.895x

1.38 = (0.895/1.38) x

1.38 = 0.65x

x= 0.65/1.38

???

2) I = Imax (1-e ^-Rt/L) , R=30, L=0.01 - find t in seconds for current to reach 95%

= I/Imax = 1- e -Rt/1

=I/Imax+1 = -e -Rt/1

-ln (I/Imax+1) = -Rt/1 lne

-Rt/1= -ln(I/Imax+1)

-Rt= -ln(I/Imax +1) (l)

t= -ln (1/0.95 +1) (0.01)/-30

???

3) PV^Y = K , make Y the subject

V^Y = K/P

lnV^Y = ln K/P

YlnV = ln K/P

Y = K/P / lnV

4) V= Vmax exp -R/1 t , make t the subject

V/Vmax = e -R/1 t

ln V/Vmax = ln(e- R/1 t)

ln V/Vmax = -R/1 t lne

ln (V/Vmax) = -R/1 t

t = ln (V/Vmax) L/ -R