In the coordinate plane, points (x, 5) and (7, y) are on line k. If line k passes through the origin and has slope 5/7, then x + y =	Choices
A) 13 B) 14 C) 9 D) 10 E) 12
Line k passes through the origin and has slope 5/7 means that its equation is y=5/7*x.   Thus: (x, 5)=(7,5) and (7, y) = (7,5) --&gt; x+y=7+5= 
<gadget id="calculator">7+5</gadget>
<output>12</output>
12.   Answer: 12
<result>E</result>
In the coordinate plane, points (x, 5) and (7, y) are on line k. If line k passes through the origin and has slope 5/7, then x + y =