I need help understanding this!

The basic idea is that multiplying by 10 just moves the decimal point one place to the right.  It makes the number bigger.

4.8 x 10 = 48

4.8 x 10 x 10 = 48 x 10 = 480

Each time you multiply by another 10, the decimal point moves one more time.

The expression says you're going to multiply by 10 five times in a row.  So that will move the decimal point 5 places to the right.

So what do you get if you move the decimal in 4.8 five places to the right?

y=3n + 1

step-by-step explanation:

this is wrong because it says the second number is one less and i added one instead

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!