Question 30318
{{{ 12(4r-5r/6) + 20 = 19r - 15 + 45r/2 }}} First distribute the 12
{{{ 48r-60r/6 + 20 = 19r - 15 + 45r/2 }}} reduce the fraction on the left
{{{ 48r-10r + 20 = 19r - 15 + 45r/2 }}} combine like terms on the left
{{{ 38r + 20 = 19r - 15 + 45r/2 }}} change the 19r to a denominator of 2
{{{ 38r + 20 = 38r/2 - 15 + 45r/2 }}} combine like terms on the right
{{{ 38r + 20 = 83r/2 - 15 }}} Make ALL terms have a denom of 2
{{{ 76r/2 + 40/2 = 83r/2 - 30/2 }}} since this is an equation and all are like denoms.  Drop them.
{{{ 76r + 40 = 83r - 30 }}} subtract 76r from both sides
{{{ 40 = 7r - 30 }}} add 30 to each side
{{{ 70 = 7r }}} divide by 7 on each side
{{{ 70/7 = r }}} reduce
{{{ 10 = r }}}  Watch your multiplying.  Doing this at 1 am you can make a silly little mistake like 12*4 = 36 and you will get a messed up answer :-P