Question 657334
In this case, you would write an equation.  The equation must have one variable, not two.

So, the equation would be: 1490=B+(B-150).
1490= 2b-150
1490-150=2b
1340=2b
1340/2=b
670=b
Now see if  building a is 670 feet.

670+(670+150)=1490?
670+820=1490

So,
Building A is 670 feet, and Building B is 820 feet.