Find the missing term so that r2 + _____ + 100 forms a perfect square trinomial.
A. 10r B. 20r C. −10r D. −20r

Respuesta :

Answer:

B    20r

Step-by-step explanation:

r² +      + 100    

r² = (r       ) (     )   signs are all positive.   100 = (10)  (10) last number.  so

(r + 10)(r + 10)

r(r+ 10) + 10(r + 10)

r² + 10r + 10r + 100

r² + 20r + 100