Exercise 48 Page 57

We want to use a table to find the two consecutive integers between which the solution lies for the given equation. -115b+80=-489 To choose a good starting point, let's pretend that the equation is a bit more simple. -115b=-489 What multiplied by -115 would get us close to -489? This isn't the easiest thing to calculate in our heads, but it may be easier to get that - 115 * 5=-575. Let's start our table at b=5 and work up from there.

Since our equation is -115b+80=-489, and -495<-489<-380, we know that the solution must lie between 4 and 5. 4