Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Hosam
Lv 6
Hosam asked in Science & MathematicsMathematics · 7 years ago

Given three points A(1, 2) , B(7, 4), C(5, 7). Find the points P(x,y) such that PB = 2 PA, and PC = 3 PA ?

1 Answer

Relevance
  • Pope
    Lv 7
    7 years ago

    There are no solutions. The two conditions describe circles, which do not intersect.

    PB = 2PA

    √[(x - 7)² + (y - 4)²] = 2√[(x - 1)² + (y - 2)²]

    (x - 7)² + (y - 4)² = 4[(x - 1)² + (y - 2)²]

    x² + y² - 14x - 8y + 65 = 4x² + 4y² - 8x - 16y + 20

    3x² + 3y² + 6x - 8y - 45 = 0

    PC = 3PA

    √[(x - 5)² + (y - 7)²] = 3√[(x - 1)² + (y - 2)²]

    (x - 5)² + (y - 7)² = 9[(x - 1)² + (y - 2)²]

    x² + y² - 10x - 14y + 74 = 9x² + 9y² - 18x - 36y + 45

    8x² + 8y² - 8x - 22y - 29 = 0

    So there you have the two circles. If you can find a point of intersection, then that represents a solution. But like I said, there are no points of intersection.

Still have questions? Get your answers by asking now.