Hydroelectricity because it is a renewable resource of water usage whereas the other 3 are just different forms of nonreneable forms of energy meaning they take millions of years for us to get them back
I suppose you mean the slope of a line that is parallel to y = (1/2)x + 3.
This equation is written in slope-intercept form, which means that the number in front of x represents the slope of the line. The other number represents the y-intercept.
A line that is parallel to another line, will be a line with the same slope. Since the slope of y = (1/2)x + 3 is (1/2), the slope of a line parallel to this line is (1/2) as well.
= 68%