Answer:
Step-by-step explanation:
You are given two points whose y values are the same. There is no need to use the distance formula. The x values alone will give you the length of the line.
to get to the y axis you have to go 12 units to the right.
To get from the y axis to 9, you have to go 9 more units to the right.
The total is 9 + 12 = 21
If you insist to see this done with the formula, it would look like this.
d = sqrt( y2 - y1)^2 + (x2 - x1)^2 )
y2 = 6
y1 = 6
x2 = -12
x1 = 9
d = sqrt ( (6 - 6)^2 + (-12 - 9)^2 )
d = sqrt( 0 + ( -21 )^2 )
d = sqrt( 441)
d = 21 the same thing you got just be reasoning it out.
The first method works only if either both xs are the same or both ys are the same.
