Explanation:
I assume the question is about the distance between both points.
2 points in the coordinate grid create a right-angled triangle :
their direct connection (distance) is the Hypotenuse (the baseline, it is the side opposite of the 90° angle), and the x and y coordinate differences are the legs.
so, we can use Pythagoras to get the distance.
c² = a² + b²
c being the Hypotenuse, a and b being the legs.
so,
distance² = (-9 - -7)² + (-4 - -1)² = (-9 + 7)² + (-4 + 1)² =
= (-2)² + (-3)² = 4 + 9 = 13
distance = sqrt(13) = 3.605551275...
just in case, if you needed the line equation connecting these 2 points, I would assume the slope-intersect form
y = ax + b
"a" being the slope, "b" being the y-intersect (the y-value when x = 0).
the slope is always the ratio (y coordinate difference / x coordinate difference) when going from one point on the line to another.
using the 2 given points
x changes by +2 (from -9 to -7).
y charges by +3 (from -4 to -1).
the slope is
+3/+2 = 3/2
and our equation looks like
y = 3x/2 + b
now we use the coordinates of 1 point, e.g. (-7, -1), to get b
-1 = 3/2 × -7 + b = -21/2 + b
-1 + 21/2 = b
-2/2 + 21/2 = b
19/2 = b
our equation is then
y = 3x/2 + 19/2
or
y = (1/2)×(3x + 19)