Question

efectuar (x+8)(x+4)-(x+4)(x+5)-3(4x-3)+ 9x

Answer 1

Respuesta:

-x2 - 3x + 21

Explicación:

STEP

1

:

Equation at the end of step 1

 (((x+(8•(x+4)))-((x+4)•(x+5)))-3•(4x-3))+9x

STEP

2

:

Equation at the end of step 2

 (((x+(8•(x+4)))-(x+4)•(x+5))-3•(4x-3))+9x

STEP

3

:

Equation at the end of step 3

 (((x+8•(x+4))-(x+4)•(x+5))-3•(4x-3))+9x

STEP

4

:

STEP

5

:

Pulling out like terms

5.1     Pull out like factors :

  -x2 - 3x + 21  =   -1 • (x2 + 3x - 21)  

Trying to factor by splitting the middle term

5.2     Factoring  x2 + 3x - 21  

The first term is,  x2  its coefficient is  1 .

The middle term is,  +3x  its coefficient is  3 .

The last term, "the constant", is  -21  

Step-1 : Multiply the coefficient of the first term by the constant   1 • -21 = -21  

Step-2 : Find two factors of  -21  whose sum equals the coefficient of the middle term, which is   3 .

     -21    +    1    =    -20  

     -7    +    3    =    -4  

     -3    +    7    =    4  

     -1    +    21    =    20  

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored