Question 54711
Ax+By=C [Use the standard equation of a line]
(14%)(x)+(12%)($20,000-x)=$2,720
.14x+.12(20,000-x)=2720 
.14x+2400-.12x=2720 [Solve for x]
.14x-.12x=2720-2400
.02x=320
x=$16,000
.
14%of $16,000 = (.14)(16,000)=$2,240
12% of ($20,000-$16,000)=.12(20,000-16,000)=$480
So, $2,240+$480=$2,720