Math Problem Statement

how to find x intersect

Solution

To find the x-intercept of a line, you need to determine the point where the line crosses the x-axis. At this point, the y-coordinate is 0.

We already derived the equation of line DEDE from part b(ii). Let's go through the steps again to find the x-intercept clearly.

Steps:

  1. Find the slope of DEDE:

    • We previously calculated the slope of DEDE as 712\frac{7}{12}.
  2. Find the equation of line DEDE:

    • Using the point-slope form of the equation of a line: yy1=m(xx1)y - y_1 = m(x - x_1) where mm is the slope, and (x1,y1)(x_1, y_1) is a point on the line.

    • Let's use point D(4,2)D(-4, 2) and the slope m=712m = \frac{7}{12} to write the equation of line DEDE: y2=712(x(4))=712(x+4)y - 2 = \frac{7}{12}(x - (-4)) = \frac{7}{12}(x + 4) Simplifying: y2=712x+7×412=712x+2812=712x+73y - 2 = \frac{7}{12}x + \frac{7 \times 4}{12} = \frac{7}{12}x + \frac{28}{12} = \frac{7}{12}x + \frac{7}{3} So the equation of line DEDE is: y=712x+73+2=712x+133y = \frac{7}{12}x + \frac{7}{3} + 2 = \frac{7}{12}x + \frac{13}{3}

  3. **Set ( y =

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Math Problem Analysis

Mathematical Concepts

Algebra
Coordinate Geometry
Linear Equations

Formulas

Point-slope form of a line: y - y1 = m(x - x1)
Slope formula: m = (y2 - y1) / (x2 - x1)

Theorems

The concept of the x-intercept (where y = 0)

Suitable Grade Level

Grades 9-12