Question

What is the equation of the line with an x-intercept of -1 and a y-intercept of 2?

y = 2x - 2
y = - 2x + 2
OR
y = 2x + 2

Answer 1

look if the line is ascendent, x may be positive.
When x=0, y=2 and when y=0, x=-1

y= 2x +2

Answer 2

ah! you can use too:

y-y0 = m(x-x0)

at (0, 2)

y-2 = m (x-0)
y=mx +2 [1]

m is the slope: so taking two points (0 ,2) and ( -1 , 0)

m = (2 - 0)/( 0 -(-1)) = 2

replacing in [1]

y= 2x +2