Question

give the equation of the line that goes through the points (2, -1) and (5,2)

Answer 1

first you need the slope of the line that goes through the two points

so use the slope formula

m = (y2-y1)/(x2-x1)

Answer 2

what do you get for the slope?

Answer 3

1...correct?

Answer 4

correct, m = 1

Answer 5

now use y = mx+b

Answer 6

y = mx + b

y = 1*x + b ... plug in m = 1

-1 = 1*(2) + b ... plug in x = 2 and y = -1, from the first point

-1 = 2 + b

...
...
...

b = ???

Answer 7

is it 2??

Answer 8

-1 = 2 + b

-1 - 2 = 2 + b - 2

-3 = b

b = -3

Answer 9

m = 1
b = -3

y = mx+b turns into y = 1x + (-3) and that simplifies to y = x - 3