Math Problem Statement

The line p passes through (1, -3) and (4, 6) and the line q has equation y = (4/5)x + 5. The lines p and q intersect at T. (a) Find an equation for p. (b) Find the coordinates of T.

Solution

We are tasked with solving two parts for this problem involving two lines pp and qq.

Given:

  • Line pp passes through the points (1,3)(1, -3) and (4,6)(4, 6).
  • Line qq has the equation y=45x+5y = \frac{4}{5}x + 5.
  • The lines intersect at point TT.

Part (a): Find the equation for line pp

To find the equation of line pp, we will:

  1. Determine the slope of the line using the two given points.
  2. Use the slope-point form to find the equation.

Step 1: Slope of line pp

The slope formula is: m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1} Using the points (1,3)(1, -3) and (4,6)(4, 6): m=6(3)41=6+33=93=3m = \frac{6 - (-3)}{4 - 1} = \frac{6 + 3}{3} = \frac{9}{3} = 3 Thus, the slope of line pp is 3.

Step 2: Equation of line pp

Using the point-slope form: yy1=m(xx1)y - y_1 = m(x - x_1) Substituting m=3m = 3 and the point (1,3)(1, -3): y+3=3(x1)y + 3 = 3(x - 1) Simplifying: y+3=3x3y + 3 = 3x - 3 y=3x6y = 3x - 6 Thus, the equation of line pp is y=3x6y = 3x - 6.


Part (b): Find the coordinates of point TT

To find the coordinates of point TT, we need to solve for the intersection of lines pp and qq.

Line equations:

  • Line pp: y=3x6y = 3x - 6
  • Line qq: y=45x+5y = \frac{4}{5}x + 5

We set the two equations equal to each other to find xx: 3x6=45x+53x - 6 = \frac{4}{5}x + 5 Multiplying through by 5 to eliminate the fraction: 5(3x6)=5(45x+5)5(3x - 6) = 5\left(\frac{4}{5}x + 5\right) 15x30=4x+2515x - 30 = 4x + 25 Now, collect like terms: 15x4x=25+3015x - 4x = 25 + 30 11x=5511x = 55 x=5x = 5

Now substitute x=5x = 5 back into one of the original equations to find yy. Using y=3x6y = 3x - 6: y=3(5)6=156=9y = 3(5) - 6 = 15 - 6 = 9

Thus, the coordinates of point TT are (5,9)(5, 9).


Final answers:

  1. The equation of line pp is y=3x6y = 3x - 6.
  2. The coordinates of the intersection point TT are (5,9)(5, 9).

Do you have any questions or would you like further details on any steps?

Relative Questions:

  1. How do you find the equation of a line given two points?
  2. What is the geometric meaning of the slope of a line?
  3. How do you solve a system of linear equations?
  4. What does it mean when two lines intersect?
  5. Can two non-parallel lines in a plane never intersect?

Tip:

When solving for the intersection of two lines, always check if they are parallel first (i.e., have the same slope) to avoid unnecessary calculations.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Coordinate Geometry
Slope

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Point-slope form: y - y1 = m(x - x1)
Solving a system of equations by substitution

Theorems

Two lines intersect at a point if their slopes are different
Intersection of two lines by setting equations equal

Suitable Grade Level

Grades 9-11