How do you solve #-21= 3x - 3( 3x - 9)#?

1 Answer
Nov 13, 2016

#x = 8#

Explanation:

Step 1) Expand the terms in parenthesis:

#-21 = 3x - 9x + 27#

Step 2) Combine like terms on each side of the equation, in this case you only need to be concerned with the right side of the equation:

#-21 = -6x + 27#

Step 3) Solve for #x# while keeping the equation balanced:

#-21 - 27 = -6x +27 - 27#

#-48 = -6x#

#(-48)/-6 = (-6x)/-6#

#8 = x#