How do I solve this, a + ( a - 3 ) = ( a + 2 ) - ( a + 1) ?

Question

I'm not sure how to get rid of the other two parentheses to solve. 

Answer 1

Hi Jacqueline,

 

a + (a - 3) = (a + 2) - (a + 1)

 

You can imagine writing this equation as

 

a + (1)(a - 3) = (1)(a + 2) +(-1)(a + 1)

 

Then you can multiply these 1's and -1's through using the Distributive Property. a(b + c) = ab + ac

 

So,

 

a + (1)(a) + (1)(-3) = (1)(a) + (1)(2) + (-1)(a) + (-1)(1)

 

a + a - 3 = a + 2 - a -1

 

Or

 

2a -3 = a - a + 2 -1

 

Or

 

2a - 3 = 1 where the a's on the right side cancel out.

 

2a = 4

 

Then,

 

a = 2

 

Is that clear?