for every positive 2 digit number, x, with tens digit t and units digit u, let y be the 2 digit number formed by reversing the digits of x. which of the following expressions is equivalent to x-y?
f. 9(t-u)
g. 9(u-t)
h. 9t-u
j. 9u-t
k. 0

Question

anonymous · Answer

i looked this one up...I know the answer, but i honestly can't figure out how they got it...

anonymous · Answer

lol yeah i dont know how you would get it either....

anonymous · Answer

i could look in the back of the book for the answer but i try to figure them out first but i have no flippin idea even where to start with this one

anonymous · Answer

x=10t+U
y=10u+t
x-y=10t+u-(10u+t)
x-y=9t-9u=9(t-u)

anonymous · Answer

i understand everything up until the last line...I don't know where they get the nines from

anonymous · Answer

They just collected the terms of t and u

anonymous · Answer

how do you mean

anonymous · Answer

i do its called the foil method... hang on i will draw it out

anonymous · Answer

Looking at t:
10t -(+t) = 9t
etc etc

anonymous · Answer

got ya...wow...ok over thought that

anonymous · Answer

in which he just showed you its the foil method

anonymous · Answer

ok you want another one?

anonymous · Answer

yeah

anonymous · Answer

lol ok i will open it in a new window hun.

anonymous · Answer

alright babe

anonymous · Answer

i have to draw it out so i will just randomly type something..

anonymous · Answer

ok

anonymous · Answer

x = 10t + u
y = 10u + t

x - y =10t + u - (10u +t) = 9t - 9u = 9(t-u)

anonymous · Answer

f is the answer