Just pretend "p" and "w" are funny-looking numbers and solve these the way you would if they were actual numbers.
A) -np -70 < 40
... -np < 110 . . . . . add 70
... n < -110/p . . . . for p < 0 . . . . . divide by the coefficient of n
... n > -110/p . . . . for p > 0 . . . . . dividing by a negative reverses the comparison
B) 4w - 7k = 28
... -7k = 28 - 4w . . . . subtract 4w
... k = (28 -4w)/(-7) . . . . divide by the coefficient of k
... k = (4w - 28)/7 . . . . . simplify
