Step-by-step explanation:
line equation
y = ax + b
a is the slope, b is the y-intercept.
a slope perpendicular to another slope flips x and y upside down and flips the sign.
so, the slope perpendicular to 2/7 is -7/2.
so, our desires line function looks like
y = -7/2 × x + b
to get b we use the given point (and it's x and y coordinates = values).
-8 = -7/2 × 8 + b = -7×4 + b = -28 + b
b = 20
so, the full line equation is
y = -7/2 × x + 20