Răspuns:
Explicație pas cu pas:
a) ( 7 / 2 - 29 / 10 )² - ( 81 / 20 - 77 / 20 )² =
= ( 35 / 10 - 29 / 10 )² - ( 4 / 20 )² =
= ( 6 / 10 )² - ( 1 / 5 )² =
= ( 3 / 5)² - 1 / 5² =
= 9 / 25 - 1 / 25 =
= 8 / 25
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c) ( 7 / 2 )² × ( 12 / 5)² - ( 21 / 5 )² × ( 3 / 2 )² =
= ( 7² / 4 ) × ( 12² / 5² ) - ( 7² × 3² ) / 25 × 9 / 4 =
= ( 7² / 4 ) × 144/ 25 - ( 7² × 3² ) / 25 × 9 / 4 =
→simplific pe 144 cu 4 = 36 / 1
= ( 7² × 4 × 9 ) / 25 - ( 7² × 9 ) / 25 × 9 / 4 =
= ( 7² × 9 ) / 25 × ( 4 - 9 / 4 ) =
→ l-am dat factor comun pe 7² x 9 / 25
= ( 49 × 9 ) / 25 × ( 16 - 9 ) / 4 =
= ( 441 × 7 ) / ( 25 × 4) =
= 3 087 / 100
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d) [ 29 / 5 - ( 12 / 5 )² ] × 5 / 2 + 19 / 5 - ( 19 / 10 )² =
= ( 29 / 5 - 12² / 25 ) × 5 / 2 + 19 / 5 - 19² / 10² =
= ( 145 / 25 - 144 / 25 ) × 5 / 2 + 19 / 5 - 361 / 100 =
= ( 1 / 25 ) × 5 / 2 + 19 / 5 - 361 / 100 =
= 1 / 10 + 19 / 5 - 361 / 100 → aduc fractiile la acelasi numitor comun 100
= ( 10 + 380 - 361 ) / 100 =
= 29 / 100
