how can -ab\2-ab\2=-ab

Question

a2/4-ab/2-ab/2+b2

Answer 1

Hi Sandra, we can write -ab/2 - ab/2 as (-ab - ab) / 2, since the denominators are the same.

 

Then:

 

-ab - ab = -2ab

 

Substitue:

 

(-ab - ab) / 2 = -2ab / 2 

 

Cancel the out the 2 in the numerator and denominator leaves -ab.

 

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