Write an equation for the following conditions:

[trip20]

Write an equation for the following conditions: Passing through (-4,6) and perpendicular to y=-1/4x+5?


I got this worng on a test and can't figure out why? Can someone please walk me through.

This is what I did:

First I used point-slope formula with the negative reciprocal for the perpendicular line

y-y1=m(x-x1)

y-6=4(x-(-4))

y-6=4x+16

0=4x-y+22

 

[alpepe]

so your at

O=4x-y+22

ok so if you subtract 22 from each side you have

-22=4x-y

am I wrong

 

[stapel]

-22=4x-y

am I wrong

You are no more wrong than was the original poster; you only formatted the equation differently. And since the question didn't specify the formatting, that shouldn't have been the reason why the answer was counted as being incorrect.

What the reason actually was, though, I cannot guess. The answer looks fine to me.

Eliz.

 

[Denis]

Write an equation for the following conditions: Passing through (-4,6) and perpendicular to y=-1/4x+5?

0=4x-y+22

Well, correct, BUT I guess they wanted to see the standard y = mx + b;
so add y to both sides to get: y = 4x + 22

Btw, (-4,6) is also the intersection of the 2 lines.

 

[stapel]

I guess they wanted to see the standard y = mx + b...

Actually, "y = mx + b" is "slope-intercept" form. "Standard" form is almost always either "Ax + By = C" or "Ax + By + C = 0". And, either way, the instructions didn't mention it.

Eliz.