A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

(Please Help will FAN and Medal!) ←→ ←→ AB and BC form a right angle at point B. If A = (-3, -1) and ←→ B = (4, 4), what is the equation of BC?

  • This Question is Open
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    A.) x + 3y = 16 B.) 2x + y = 12 C.) -7x − 5y = -48 D.) 7x − 5y = 48

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Its my final question

  3. mathstudent55
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1435677378715:dw|

  4. mathstudent55
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Look at line AB. You know two points it goes through, so you can find its slope. |dw:1435677554492:dw|

  5. mathstudent55
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Once you know the slope of line AB, you can find the slope of its perpendicular. The slopes of perpendiculars are negative reciprocals. Then you will know the slope of line BC and a point it goes through, B(4, 4). That is enough information to find the equation of line BC.

  6. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay thank you!

  7. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    is C (6,2)?

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    nevermind i got it Thank you for all your help!

  9. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    C.) -7x − 5y = -48 was the answer ^.^

  10. mathstudent55
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    1. Find the slope of line AB using points A(-3, -1) and B(4, 4). \(slope = m = \dfrac{y_2 - y_1}{x_2 - x_1} = \dfrac{4 - (-1)}{4 - (-3)} = \dfrac{4 + 1}{4 + 3} = \dfrac{5}{7} \) 2. Find the slope of the perpendicular, line BC: The slopes of perpendicular lines are negative reciprocals. That means their product is -1. That also means each one is the negative reciprocal of the other. \(slope~of~line~AB = \dfrac{5}{7} \) \(slope~of~line~BC = -\dfrac{7}{5} \) 3. Line BC has slope \(-\dfrac{7}{5} \) and passes through point (4, 4) \(y = mx + b\) \(y = -\dfrac{7}{5}x + b\) Use point (4, 4) to find b: \(4 = -\dfrac{7}{5} \times 4 + b\) \(4 = -\dfrac{28}{5} + b\) \(\dfrac{20}{5} = -\dfrac{28}{5} + b\) \(\dfrac{48}{5} = b\) \(b = \dfrac{48}{5} \) The equation of the line is: \(y = -\dfrac{7}{5} x + \dfrac{48}{5} \) Multiply both sides by 5: \(5y = -7x + 48\) Add 7x to both sides: \(7y + 5x = 48\) If you multiply this equation by -1 on both sides, you do get -7x - 5y = -48 which is your answer.

  11. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.