Math Problem Statement

The line V passes through the points (-5,3) and (7,-3) and the line W passes through the points (2,-4) and (4,2). The lines V and W intersect at the point A. Work out the coordinates of point A

Solution

To find the coordinates of the intersection point AA between the lines VV and WW, we need to find the equations of both lines and solve them simultaneously.

Step 1: Find the equation of line VV

The line VV passes through the points (5,3)(-5, 3) and (7,3)(7, -3).

First, calculate the slope mVm_V of line VV using the formula: mV=y2y1x2x1=337(5)=612=12m_V = \frac{y_2 - y_1}{x_2 - x_1} = \frac{-3 - 3}{7 - (-5)} = \frac{-6}{12} = -\frac{1}{2}

Now, use the point-slope form of the equation of a line yy1=m(xx1)y - y_1 = m(x - x_1) with one of the points, say (5,3)(-5, 3): y3=12(x(5))y - 3 = -\frac{1}{2}(x - (-5)) y3=12(x+5)y - 3 = -\frac{1}{2}(x + 5) y3=12x52y - 3 = -\frac{1}{2}x - \frac{5}{2} y=12x52+62y = -\frac{1}{2}x - \frac{5}{2} + \frac{6}{2} y=12x+12y = -\frac{1}{2}x + \frac{1}{2}

So, the equation of line VV is: y=12x+12y = -\frac{1}{2}x + \frac{1}{2}

Step 2: Find the equation of line WW

The line WW passes through the points (2,4)(2, -4) and (4,2)(4, 2).

First, calculate the slope mWm_W of line WW using the formula: mW=2(4)42=62=3m_W = \frac{2 - (-4)}{4 - 2} = \frac{6}{2} = 3

Now, use the point-slope form with one of the points, say (2,4)(2, -4): y(4)=3(x2)y - (-4) = 3(x - 2) y+4=3(x2)y + 4 = 3(x - 2) y+4=3x6y + 4 = 3x - 6 y=3x64y = 3x - 6 - 4 y=3x10y = 3x - 10

So, the equation of line WW is: y=3x10y = 3x - 10

Step 3: Solve the system of equations

Now, solve the two equations simultaneously:

  1. y=12x+12y = -\frac{1}{2}x + \frac{1}{2}
  2. y=3x10y = 3x - 10

Set them equal to each other: 12x+12=3x10-\frac{1}{2}x + \frac{1}{2} = 3x - 10

Multiply through by 2 to eliminate the fractions: x+1=6x20-x + 1 = 6x - 20

Now, solve for xx: 1+20=6x+x1 + 20 = 6x + x 21=7x21 = 7x x=3x = 3

Substitute x=3x = 3 into one of the original equations, say y=3x10y = 3x - 10: y=3(3)10=910=1y = 3(3) - 10 = 9 - 10 = -1

Final Answer:

The coordinates of point AA, where the lines intersect, are (3,1)(3, -1).

Would you like any further details or clarifications? Here are five related questions you might find interesting:

  1. How do you calculate the slope of a line?
  2. What is the point-slope form of a line equation?
  3. How can you determine if two lines are parallel?
  4. What are the conditions for two lines to intersect at right angles?
  5. How do you find the distance between two points on a coordinate plane?

Tip: When solving simultaneous equations, it is often easier to eliminate fractions by multiplying through by the denominator.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Simultaneous Equations
Slope of a Line
Intersection of Lines

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Point-slope form of a line: y - y1 = m(x - x1)
Equation of a line: y = mx + c
Solving simultaneous equations

Theorems

Two lines intersect when their equations yield a common solution.

Suitable Grade Level

Grades 9-10