Which equation represents a line that passes through $(5,1)$ and has a slope of $\frac{1}{2}$?


A$y-5=\frac{1}{2}(x-1)$
B$y-\frac{1}{2}=5(x-1)$
C$y-1=\frac{1}{2}(x-5)$
D$y-1=5\left(x-\frac{1}{2}\right)$

Verified Answer :

  • Use the point-slope formula \(y - y_1 = m(x - x_1)\).
  • Substitute the given point \((5, 1)\) and slope \(m = \frac{1}{2}\) into the formula.
  • The resulting equation is \(y - 1 = \frac{1}{2}(x - 5)\).
  • Final Answer: \(\boxed{y - 1 = \frac{1}{2}(x - 5)}\).

Explanation

  1. Understanding the Point-Slope Formula

The problem asks for the equation of a line that passes through the point \((x_1, y_1) = (5, 1)\) with a slope of \(m = \frac{1}{2}\). To represent this line, we use the point-slope form of a linear equation, which is given by:
\[y - y_1 = m(x - x_1)\]
In this formula, \(m\) represents the slope of the line, and \((x_1, y_1)\) is a specific point that the line passes through. Having identified the given parameters as \(m = \frac{1}{2}\), \(x_1 = 5\), and \(y_1 = 1\), we are ready to substitute these into the standard formula.

  1. Deriving and Verifying the Equation

To find the equation, we substitute the given coordinates and the slope into the point-slope formula:
\[y - 1 = \frac{1}{2}(x - 5)\]
This equation relates every point \((x, y)\) on the line to the given reference point \((5, 1)\) through the constant slope of \(\frac{1}{2}\). By comparing this result to the provided options, we can identify which equation is correct. The correct equation is clearly \(y - 1 = \frac{1}{2}(x - 5)\).

Examples

The point-slope form is incredibly useful in everyday engineering and construction. For example, if you are designing a wheelchair ramp and know that it needs to pass through a specific point (the start of the ramp at ground level) and maintain a constant slope (like a 1:12 ratio for accessibility), you can use this formula to map out the entire structure. Just as we found the equation of a line from a point and a slope, engineers use these linear models to ensure ramps are safe, functional, and meet accessibility standards.