The graph of a straight line intersects the coordinate axes at the points P(0,5) on the y-axis and Q(8,0) on the x-axis.
Answer the following questions related only to what can be observed from this graph.
a. (i) Describe, in words, how the two intercepts P and Q enable you to estimate the slope of the line without using any coordinate-geometry formula.
b. (ii) State whether the slope of the line is positive, negative, zero or undefined and justify your answer purely on the basis of its graphical position.
c. (iii) A student claims that the numerical value of the slope is 85. Examine this claim using the graphical information and explain why it is or is not correct.