The equations above are all in the format 
, where 
= the gradient, or slope.
So, in the first question,
, the gradient would be 4, because 4 is in this equation (the number before the 
).
The gradient of a line perpendicular to this line is equal to the negative reciprocal of the gradient of the line. A better way to explain it is if = the gradient of the line and <u />
= the gradient of the perpendicular line then:
So in the first question, the gradient of the perpendicular line is
.
So, in the first question,
The gradient of a line perpendicular to this line is equal to the negative reciprocal of the gradient of the line. A better way to explain it is if
So in the first question, the gradient of the perpendicular line is