Question

For the straight line defined by the points (1,51) and (3,91), determine the slope and y-intercept.

Answer 1

Explanation:

Given a straight line defined by the points (1,51) and (3,91),

x1 = 1, y1 = 51, x2 = 3 and y2 = 91

Slope of the line m = ∆y/∆x

m = y2-y1/x2-x1

m = 91-51/3-1

m = 40/2

m = 20

Hence the slope of the line is 20.

Given the equation of a line y = mx+c

To get the y intercept of the line c, we will substitute one of the give points and the slope into the equation as shown;

Using the point (1,51) and m = 20,

Substitute into the equation y = mx+c

51 = 20(1)+c

51 = 20+c

c = 51-20

c = 31

Hence the slope is 20 and the y intercept of the line is 31