Let a and b represent the heights of the corresponding buildings (in meters).
... a = b +271 . . . . . . . a is 271 meters taller than b
... 2b -a = 211 . . . . . . if a is subtracted from twice b, the result is 211
Use the expression for a in the first equation to substitute for a in the second.
... 2b - (b+271) = 211
... b = 482 . . . . . . . . . . . simplify and add 271
... a = b +271 = 753
Building a is 753 meters tall; building b is 482 meters tall.
