Math Problem Statement

Find the equation of the straight line y = k * x + q going through the points A = [-1, 3] and B = [2, 6].

Solution

We are asked to find the equation of the straight line y=kx+qy = k \cdot x + q, which passes through the points A(1,3)A(-1, 3) and B(2,6)B(2, 6). To do this, we need to find the values of kk (the slope) and qq (the y-intercept).

Step 1: Calculate the slope kk

The slope kk of the line passing through two points A(x1,y1)A(x_1, y_1) and B(x2,y2)B(x_2, y_2) is given by: k=y2y1x2x1k = \frac{y_2 - y_1}{x_2 - x_1} Substituting the coordinates of A(1,3)A(-1, 3) and B(2,6)B(2, 6): k=632(1)=33=1k = \frac{6 - 3}{2 - (-1)} = \frac{3}{3} = 1

Step 2: Find the y-intercept qq

Now that we know the slope k=1k = 1, we can use the equation of the line y=kx+qy = k \cdot x + q to find qq. We can substitute the coordinates of one of the points, say point A(1,3)A(-1, 3), into the equation.

Using A(1,3)A(-1, 3): 3=1(1)+q3 = 1 \cdot (-1) + q 3=1+q3 = -1 + q q=4q = 4

Final Equation of the Line:

The equation of the line is: y=1x+4or simplyy=x+4y = 1 \cdot x + 4 \quad \text{or simply} \quad y = x + 4

So, k=1k = 1 and q=4q = 4.

Would you like more details or have any questions?

Here are some related questions for further exploration:

  1. How do you derive the equation of a line from different forms (e.g., point-slope)?
  2. What is the geometric significance of the slope kk?
  3. How can you calculate the distance between two points in a plane?
  4. What happens to the line equation if one of the points is on the y-axis?
  5. How can the midpoint formula help when finding the center between two points?

Tip: Always verify the slope calculation before substituting into the line equation to avoid sign errors.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Algebra
Coordinate Geometry

Formulas

Slope formula: k = (y2 - y1) / (x2 - x1)
Line equation: y = k * x + q

Theorems

Point-Slope Formula

Suitable Grade Level

Grades 8-10