Answer:
C. 2x + 40 = 2868
Step-by-step explanation:
In this equation, x is the height of the Empire State Building.
If Sears Tower is 40 feet taller than x, and the sum of their heights is 2868, what we have to do to find x is subtract 40 from 2868, then divide by 2.
This is the same as multiplying x by 2, then adding 40 (just backwards).
Let me demonstrate..
2868 - 40 = 2828
2828 / 2 = 1414
x = 1414
Now let's try the other way..
2x + 40 = 2868
Let x = 1414
2 x 1414 = 2828
2828 + 40 = 2868
And there's your answer again!