Answer:
As shown in picture,
Line A passes (3, 3) and (4, 5)
=> Gradient of line A = (y2 - y1)/(x2 - x1) = (5 - 3)/(4 - 3) = 2
Line B passes (0, 4) and (4, 0)
=> Gradient of line B = (y2 - y1)/(x2 - x1) = (0 - 4)/(4 - 0) = -4/4 = -1
Hope this helps!
:)