Question

resolva o truque álgebrico:

a) 39 × 31 =

b) 28 × 32 =​

por favor!!
​

Answer 1

Resposta:

a) 39 × 31 =(35+4)*(35-4) =35²-4² =1225-16

= 1209

b) 28 × 32 =​ (30-2)*(30+2)=30²-2² =900-4

=896