Find an equation of the line through (-1,3) and perpendicular to the line through (0,1) and (2,3)

Y=mx+c

The gradient of the perpendicular line is 3-1/2-0, or 2/2, which is 1.

the gradient therefore is - 1 you have to swap the denominator and numerator then make it negative. In this case 1/1 turned upside down is still 1/1 and then you make it negative to get - 1.

so y=-1x+c

To find c look at where this line would be if it had the same x coordinate as the one provided, in this case it would be (-1,1). The difference in the y axis is 2, so you need to add 2 to the second number to get (-1,3) so c=2

THis means that the equation is:

y=-1x+2