Question

From m2 + 5m - 7 subtract m2 - 3m 4. A) 8m - 3 B) 2m - 11 C) 2m2 + 2m - 11 D) 2m2 + 8m - 11

Answer 1

The answer is:  [A]:  " 8m − 3 " .
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Explanation:
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(m² + 5m − 7) − (m² − 3m − 4) =

    (m² + 5m − 7) − 1(m² − 3m − 4)  =

     (m² + 5m − 7) − 1m²  + 3m + 4) =

m² + 5m − 7 − m²  + 3m + 4 ;
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Now, combine the "like terms" :
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m² − m² = 0 (cancel out).

+5m +3m = +8m ;

− 7 + 4 = -3 ;
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And we are left with:
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 " 8m − 3 " ;  which is: Answer choice:  [A] .
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