Maximizing Efficiency: Rearranging Formulas for Quick Calculations

[faisal]

can u just check if these questions are correct.
a) P=W/t for t
answer t=w/p
b)e=IR+Ir for I
ANSWER, I=R/e+r/e
c) x=a/y for y
ANSWER-y=a/x
d)F=ma for a
answer F/m=a

 

[marlon]

b) should be : I = e/(R + r)
c) should be : y = a/x
regards
marlon

 

[recon]

Expressed step by step for clarity the solution to (b) is as follows:

e = IR + Ir
e = I(R + r)
I = e/(R +r)