Question

Write an equation of the line that is perpendicular to y = 1 2 x + 3 and passes through the point (10, -5).

Answer 1

y=mx+c

1) FIND M

Perpendicular lines formula
m1 x m2 = -1
- gradient of the lines multiplied together equals to -1

Substitute
m1 x m2 = -1
12 x m2 = -1
m2 = -1/12
m2 = -0.083

2) FIND C
Now we know m, y and x, so we can find c.
(x,y) -> (10,-5)

y=mx+c
-5=-0.083*10+c
-5=0.83+c
-5-0.83=c
c=-5.83

So the equation would be
y=-0.08x+5.83

Answer 2

A) y = -2x + 15

Explanation: