Product of (x+y+2)(y+1)

x ( y + 1) + y ( y + 3) + 2

Step-by-step explanation:

( x + y + 2) ( y + 1)

x ( y + 1) + y ( y + 1) + 2 ( y + 1)

expanding the bracket

( xy + x) + ( y2 + y) + ( 2y + 2)

removing the bracket

xy + x + y2 +y + 2y + 2

collecting like terms

xy + x + y2 + 3y + 2

given as: x(y + 1) + y ( y + 3) + 2

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!