Question

Factorise this..
-21+10r-r²
only correct answers pls​

Answer 1

Step-by-step explanation:

-r²+10r-21

-r²+7r+3r-21

r(-r+7)-3(-r+7)

(r-3)(-r+7)

Answer 2

Answer:

(7+r)(3-r)

Step-by-step explanation:

-21+10r-r² = -21+7r+3r-r²

                = 7(3-r)+r(3-r)

                = (7+r)(3-r)