Determine the Equation of a Line: Slope of 1/2 and Passing Through (5, 17.5)

Question

A line has a slope of 12 \frac{1}{2} and passes through the point (5,1712) (5,17\frac{1}{2}) .

Which expression corresponds to the line?

Video Solution

Solution Steps

00:00 Find the algebraic representation of the function
00:03 We'll use the linear equation
00:09 We'll substitute the point according to the given data
00:18 We'll substitute the line's slope according to the given data
00:21 We'll continue solving to find the intersection point
00:32 We'll isolate intersection point B
00:39 This is the intersection point with the Y-axis
00:42 Now we'll substitute the intersection point and slope in the linear equation
00:49 And this is the solution to the question

Step-by-Step Solution

To determine the line's equation, we'll follow these steps:

  • Use the point-slope form of a line, given by yy1=m(xx1) y - y_1 = m(x - x_1) .
  • Substitute m=12 m = \frac{1}{2} , x1=5 x_1 = 5 , and y1=1712 y_1 = 17\frac{1}{2} into the equation.
  • Solve for y y to put the equation in slope-intercept form.

Now, let's work through the steps:

Given the point (5,1712) (5, 17\frac{1}{2}) and slope m=12 m = \frac{1}{2} , our start point is the point-slope form:
y1712=12(x5) y - 17\frac{1}{2} = \frac{1}{2}(x - 5) .

Convert the mixed number to an improper fraction: 1712=352 17\frac{1}{2} = \frac{35}{2} .

Thus, the equation becomes y352=12(x5) y - \frac{35}{2} = \frac{1}{2}(x - 5) .

Distribute the slope on the right-hand side:
y352=12x52 y - \frac{35}{2} = \frac{1}{2}x - \frac{5}{2} .

To solve for y y , add 352 \frac{35}{2} to both sides:
y=12x52+352 y = \frac{1}{2}x - \frac{5}{2} + \frac{35}{2} .

Combine the fractions on the right-hand side:
y=12x+302 y = \frac{1}{2}x + \frac{30}{2} , which simplifies to y=12x+15 y = \frac{1}{2}x + 15 .

Therefore, the equation of the line in slope-intercept form is y=12x+15 y = \frac{1}{2}x + 15 .

Comparing this with the multiple-choice options, the correct answer is:

y=12x+15 y = \frac{1}{2}x + 15

Answer

y=12x+15 y=\frac{1}{2}x+15