Question

Simplify (7x^2− 2x + 9) + (3x^2+ 15x − 4).

Answer 1

The answer is 10x^2+13x+5
I hope that helped

Answer 2

The simplified answer is:   " 10x² + 13x + 5 " .
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Explanation:
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Given:
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 (7x²− 2x + 9) + (3x²+ 15x − 4) ;

→ Rewrite as:   (7x²− 2x + 9) + 1(3x²+ 15x − 4)
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Considering the following portion of the expression:
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   "  1(3x²+ 15x − 4) " ;
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Note the "distributive property of multiplication" :
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  a(b + c) = ab + ac ;

  a(b − c) = ab + ac ;
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Likewise:

 a(b + c − d) = ab + ac − ad ;
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   So;       1(3x²+ 15x − 4) = (1*3x²) + (1*15x) − (1*4)  ; 

               =  3x² + 15x − 4

Bring down the: "(7x²− 2x + 9)" ;  and rewrite the expression:
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          7x² − 2x + 9 + 3x² + 15x − 4 ;

Combine the "like terms" :

  +7x² + 3x² =  + 10x² ;

  - 2x + 15x = + 13x ; 
 
  + 9 − 4 = + 5 ; 
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and rewrite the expression:
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   which is:   " 10x² + 13x + 5 " .
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