Answer:
Key idea: Anytime we have two true equations, we can add or subtract them to create another true equation.
For example, here are two very basic true equations:
2 = 22=22, equals, 2
5 = 55=55, equals, 5
We can add these equations together to create another true equation:
2+ 57=2=5=7
Or we can subtract these equations to create another true equation:
2− 5−3=2=5=−3
Here's another example with more complicated equations:
2x+3+ 4x+16x+4=7=9=16
