Question

What is an equation of the line that passes through the points (1, 2) and (2, -1)?

Answer 1

Answer:

y = -x + 3

Step-by-step explanation:

The equation of a straight line is generally written as;

y = mx + b

where m is the slope and b is the intercept

To get the slope we use the slope formula

Mathematically, that is;

m = (y2-y1)/(x2-x1) = (-1-2)/2-1 = -3/1 = -1

To get the intercept we equate any of the points to the partial equation that we have;

From;

y = -x + b

2 = -1 + b

b = 1 + 2 = 3

So the equation is;

y = -x + 3