To be able to do the problem 5(10 + 4) mentally, Zack does 50 + 20 instead of 5(14).
Zack is using which of the following properties?
associative
commutative
inverse
distributive

Step-by-step explanation:

the distrubutive property.

Definition: The distributive property lets you multiply a sum by multiplying each addend separately and then add the products.

eg:

where is the rest of the

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!