Question

What is an equation for the line that passes through the coordinates (-1,2) and (7,6) ?

Answer 1

Using y = mx + b, insert the points as follows:

2 = -1m + b
6 = 7m + b

Now isolate b:

b = 2 + m
b = 6 - 7m

Next set b = b, then isolate and solve for m:
2 + m = 6 - 7m

Place like terms on the same side:
7m + m = 6 - 2
8m = 4
m = 4/8
m = 1/2

Now find the value of b using the value found for m:

b = 2 + m
b = 2 + 1/2
b = 4/2 + 1/2
b = 5/2

Therefore the equation of the line is:
y = x/2 + 5/2
y = (x + 5)/2

Answer 2

did @hero help you or do you still not understand

Answer 3

What is there to not understand? Insert the points, solve for the variables, find their values, then insert the values into the equation of the line.