y = mx + b
"m" is the slope, "b" is the y-intercept
You need to find "m" and "b"
When lines are perpendicular, they have opposite slopes (the sign and number is flipped)
For example:
slope is 2
perpendicular line's slope is -1/2
slope is -4/5
perpendicular line's slope is 5/4
The given line's slope is 1/2, so the perpendicular line's slope is -2.
y = -2x + b
To find "b", you can plug in the point (2,7) into the equation
y = -2x + b
7 = -2(2) + b
7 = -4 + b Add 4 on both sides
11 = b
y = -2x + 11