Question

(a -b) . (a² + ab + b²) sendo a= 2 e b= 1/2

Answer 1

$(2- \frac{1}{2} ).( 2^{2} + 2. \frac{1}{2} + \frac{1}{2}^{2} ) \\ \\ ( \frac{4-1}{2} ).(4+ \frac{2}{2} + \frac{1}{4} ) \\ \\ \frac{3}{2} . ( \frac{16+4+1}{4} ) \\ \\ \frac{3}{2} . \frac{21}{4} \\ \\ \frac{63}{8}$

Answer 2

(a -b) . (a² + ab + b²) sendo a= 2 e b= 1/2a - b =  2 - 1/2 ==> mmc = 2

4 -1 ==> 3/2
  2
============================== 2^2 + 2.1/2 + (1/2)^24 +2/2 + 1/4    ==> 4+1+1/4 ==> 5+1/4
 20+1 ==> 21/4
    4

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(a -b) . (a² + ab + b²)
3/2 . 21/4 ==>  63/8