Next we combine like terms: 2x + 12x - 8 = 14x - 8
None of the answers without parenthesis match the formula above so I will factor out a 2
14x - 8 = 2( 7x - 4 )
Notice how I factored out the 2 putting the result of dividing the equation by 2 inside the parenthesis and then moving a 2 to the outside of the parenthesis.
Based off of the information you gave, the equation for this would be y=$25x+100 (x is the amount of weeks that she saves) if that was what you were asking for ...