The equation of line [tex]\( QR \)[/tex] is [tex]\( y = -\frac{1}{2}x + 1 \)[/tex].

Write an equation of a line perpendicular to line [tex]\( QR \)[/tex] in slope-intercept form that contains point [tex]\( (5,6) \)[/tex].

A. [tex]\( y = 2x + 6 \)[/tex]
B. [tex]\( y = -\frac{1}{2}x + \frac{17}{2} \)[/tex]
C. [tex]\( y = -\frac{1}{2}x + \frac{7}{2} \)[/tex]
D. [tex]\( y = 2x - 4 \)[/tex]



Answer :

Let's solve this step-by-step:

1. Identify the Slope of Line QR:

The given equation of line QR is:
[tex]\[ y = \frac{-1}{2}x + 1 \][/tex]
This is in the slope-intercept form [tex]\( y = mx + b \)[/tex], where [tex]\( m \)[/tex] is the slope. Here, the slope [tex]\( m \)[/tex] of line QR is [tex]\( \frac{-1}{2} \)[/tex].

2. Find the Slope of the Perpendicular Line:

The slope of a line perpendicular to another line is the negative reciprocal of the slope of the original line. The negative reciprocal of [tex]\( \frac{-1}{2} \)[/tex] is [tex]\( 2 \)[/tex]. Therefore, the slope of the perpendicular line is [tex]\( 2 \)[/tex].

3. Use the Point-Slope Form to Find the Y-Intercept:

We need to find the equation of the line with the slope [tex]\( 2 \)[/tex] that passes through the point (5, 6). The equation of a line in slope-intercept form is:
[tex]\[ y = mx + b \][/tex]
We know [tex]\( m = 2 \)[/tex], so we substitute [tex]\( m \)[/tex], [tex]\( x = 5 \)[/tex], and [tex]\( y = 6 \)[/tex] into the equation to find [tex]\( b \)[/tex]:
[tex]\[ 6 = 2 \cdot 5 + b \][/tex]
Simplifying this:
[tex]\[ 6 = 10 + b \][/tex]
Solving for [tex]\( b \)[/tex]:
[tex]\[ b = 6 - 10 \][/tex]
[tex]\[ b = -4 \][/tex]

4. Write the Final Equation:

Now that we have the slope and the y-intercept, we can write the equation of the line in slope-intercept form:
[tex]\[ y = 2x - 4 \][/tex]

Thus, the equation of the line perpendicular to line QR and passing through the point (5, 6) is:
[tex]\[ \boxed{y = 2x - 4} \][/tex]

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