If the new line is perpendicular to the original line, they the slope for the new line should be the reciprocal and opposite of the original line. Since the original line's slope is -1/3, the slope of the new line is 3, which is the coefficient in the new equation representing the new line. Then, you create an equation to solve for "b" in the equation y=mx+b where "b" is the y-intercept. You plug in 3 for x, 4 for y, and 3 for m (you know that 3 is x and 4 is y because it says that the line must past (3,4). So the equation to solve for b should be "4=3(3)+b". Then for b you should get -5.
