Mathematical simplification Evaluation M + 6 / m ^ 2-m-2 △ 3 / M + 2 times (1-1 / M + 2)

Mathematical simplification Evaluation M + 6 / m ^ 2-m-2 △ 3 / M + 2 times (1-1 / M + 2)

The original formula = (M + 6) / (m-2) (M + 1) × (M + 2) / 3 × (M + 1) / (M + 2)
=(m+6)/3(m-2)
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First grade mathematics simplification evaluation problem, m and N after 2 is the square
8mn－〔4m2n-(6mn2+mn)〕-29mn2

8mn－[4m²n－（6mn²＋mn）]－29mn²
＝8mn－[4m²n－6mn²－mn]－29mn²
＝8mn－4m²n＋6mn²＋mn－29mn²
＝9mn－4m²n－23mn²

First simplify. Then evaluate: (B + 3a) (3a-b) - (3b-a) (a + 3b), where a = - 2, B = 3

(b+3a)(3a-b)-(3b-a)(a+3b)
=9a^2-b^2-9b^2+a^2
=10a^2-10b^2
=10*4-10*9
=-50