What is the factored form of the following expressions? d^2-19d+90 a. (d-9)(d+10) b. (d-9)(d-10) c. (d+9)(d-10) d. (d+9)(d+10)

 The correct answer is:   [B]:

                       →     [B]:   " (d − 9)(d − 10) " .

Step-by-step explanation:

To factor the following expression:

           →   "  d² −  19d + 90 " ;

What factors of:  " ⁺90 " ;  add up to: " -19 " ?

   From " ⁺90 " ; we can factor out a "10" ;

    Try "10" and "9" ;   →  10 + 9 =? -19?  ;  →  No!  { "10 + 9 = ⁺ 19" .}.

    Try "-10 and "-9" ;  →  -10 + (-9) =?  -19? ; →  -10 − 9 =?  - 19?  Yes!

So, the we have:  "-10" and "-9" ;

The expression:  " d² −  19d + 90 " ;

  →  factors into:  " (d − 10)(d − 9) " ;  which is the same as:

           ↔  " (d − 9)(d − 10) " ;

           →  which corresponds to:

           →  Answer choice:  [B]: " (d − 9)(d − 10) " .

Hope this helps!

     Best wishes to you!

ummm seems that u didnt post the attachement !