Solve SA = ars + 1
for s

s = (SA - 1)/ar

Step-by-step explanation:

from the question SA = ars + 1 we want to make s the subject of the formulae

so from,

SA = ars + 1

SA- 1 = ars

divide both sides by ar

(SA - 1)/ar = ars/ar

(SA - 1)/ar = s

therefore ,

s = (SA - 1)/ar

multiplication is multiplication.   it might feel harder depending on what level of math you are in, but generally it will be the same old stuff, while implementing some new concepts and methods of solving work.