An elevator goes up 7 floors and then down 4 floors. what integer represents the change in the floor level?

3 floors.

Step-by-step explanation:

We have been given that an elevator goes up 7 floors.

We know that going up is a positive altitude, so 7 floors up will be positive 7.

Then the elevator comes down 4 floors. We know that coming down is a negative altitude, so coming down 4 floors would be floors.

The change in the floor would be floors.

Therefore, the change in the floor level is 3 floors.

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!