Jane and Jill were simplifying the expression (2x² + x) + 21-x² + x) and obtained different answers. Who is

correct and why?

2x2+x+21−x2+x

=2x2+x+21+−x2+x

=2x2+x+21+−x2+x

=(2x^2+−x^2)+(x+x)+(21)

=x^2+2x+21

answer: i realy don't get it that much can you me figer it out pleas you

step-by-step explanation:

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!