Simplify x - 9 - 3x

explain how, i'm seriously confused

combine like terms:

-3x+x

add:

-3x + x

NOTE: remember that x virtually equals 1

so -3*1+1=-1

hence, simplified x - 9 - 3x

= -2x-9

Helpful Information:

You  should also note that when combining like terms, remember that the sign before the number goes w/ the number...for example: in the expression x-9-3x, x is positive b/c it doesn't have a negative sign or anything fancy before it. We can say 9 is negative or use it to subtract since it has a minus sign before it. -3x, 3 has a minus sign so we say it's negative.

x+-3x

1+-3*1

1+-3

=-2