Expanding each integer in the expression 21x12, the result is [(2x10^1)+(1x10^0)]x[(1x10^1)+(2x10 ^0)]. Replace the 10s with x's and then multiply this expression using FOIL. Compare it with the normal integer multiplication method used above: How are they similar? show your work

(2x+1)(1x+2) = 2x^2 + 4x + x + 2 = 2x^2 + 5x + 2

i think

Step-by-step explanation:

found it xd it ok yt

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

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