Answer:
r = t + q - s
Step-by-step explanation:
t = r - q + s
goal is to isolate the variable
add q to both sides (this cancels the q out on the right side)
t + q = r - q + q + s
t + q = r + s
subtract s from both sides
t + q - s = r + s - s
t + q - s = r
In other words:
r = t + q - s
