Answer:
s = 2
r = 8
Step-by-step explanation:
subsitution is were you plug in a systerm into the other problem
since they give you R = 4s you take 4s and plug it in were r is in the other equation (subsitution)
so now you have 4s = 1/2s+7
now you want to solve for s so your going to subtract 1/2s from both sides to cancle out the 1/2s --> 4s - 1/2s = 7 --> 3 and 1/2s = 7
now divide both sides by 3 1/2 to get s alone s = 7/3 and 1/2
s = 2
now we have s we take that and plug it into r = 4s
subsitute S as 2 --> r = 4(2)
r = 8
