Question

The equation of line AB is (y-3) = 5 (x - 4). What is the slope of a line perpendicular to line AB?

A) -5
B) 5
C) -1/5
D) 1/5

My answer was C, is this right?

Answer 1

what's the slope of the line AB anyway?

Answer 2

You're right. The slope of AB is 5 and the perpendicular is - 1/5

Answer 3

Thanks! Can you help me with another one?

The equation of line CD is y = -2x - 2. Write an equation of a line parallel to line CD in slope-intercept form that contains point (4, 5).

A) y = -2x + 13
B) y = -1/2 x + 7
C) y = -1/2 x + 3
D) y = − 2x − 3

Answer 4

\[y = mx +b\]

Take the slope intercept formula and plug in what we know

We know that the slope is -2 (m), x is 4, and y is 5.

So plug those number into the equation and solve for b
\[5 = -2(4) + b\]
Simplify \[5 = -8 + b\]
add 8 to both sides \[13 = b\]
and because we are looking for a parallel line, the slopes are the same.

So, y = -2x + 13

Answer 5

omg you are a life saver :)

just one more pleeeassee :)

The equation of line WX is y = -2x - 5. Write an equation of a line perpendicular to line WX in slope-intercept form that contains point (-1, -2).

A) y = (1/2)x + 3/2
B) y = (-1/2)x + 3/2
C) y = (1/2)x - 3/2
D) y = (-1/2)x - 3/2

Answer 6

I got C