Answered

What is the [tex]$y$[/tex]-intercept of the line perpendicular to the line [tex]$y=-\frac{3}{4} x+5$[/tex] that includes the point [tex]$(-3,-3)$[/tex]?

A. [tex]-\frac{3}{4}[/tex]
B. 1
C. 7
D. [tex]-\frac{21}{4}[/tex]



Answer :

To find the [tex]\( y \)[/tex]-intercept of the line perpendicular to the line [tex]\( y = -\frac{3}{4} x + 5 \)[/tex] and passing through the point [tex]\((-3, -3)\)[/tex], we can follow these steps:

1. Find the slope of the given line:
The given line has the equation [tex]\( y = -\frac{3}{4} x + 5 \)[/tex].
- The slope ([tex]\( m \)[/tex]) of this line is [tex]\( -\frac{3}{4} \)[/tex].

2. Determine the slope of the perpendicular line:
- The slopes of perpendicular lines are negative reciprocals of each other.
- Therefore, the slope of the perpendicular line is the negative reciprocal of [tex]\( -\frac{3}{4} \)[/tex]. The negative reciprocal of [tex]\( -\frac{3}{4} \)[/tex] is [tex]\( \frac{4}{3} \)[/tex].

3. Use the point-slope form to find the equation of the perpendicular line:
- The point-slope form of a line is [tex]\( y - y_1 = m (x - x_1) \)[/tex].
- We have the point [tex]\((-3, -3)\)[/tex] and the slope [tex]\( \frac{4}{3} \)[/tex].

Plugging in these values, we get:
[tex]\[ y - (-3) = \frac{4}{3} (x - (-3)) \][/tex]
Simplifying, we have:
[tex]\[ y + 3 = \frac{4}{3} (x + 3) \][/tex]

4. Solve for the [tex]\( y \)[/tex]-intercept:
- To find the [tex]\( y \)[/tex]-intercept, we need to solve for [tex]\( y \)[/tex] when [tex]\( x = 0 \)[/tex].

Using our equation [tex]\( y + 3 = \frac{4}{3} (x + 3) \)[/tex], set [tex]\( x = 0 \)[/tex]:
[tex]\[ y + 3 = \frac{4}{3} (0 + 3) \][/tex]
[tex]\[ y + 3 = \frac{4}{3} \cdot 3 \][/tex]
[tex]\[ y + 3 = 4 \][/tex]
[tex]\[ y = 4 - 3 \][/tex]
[tex]\[ y = 1 \][/tex]

So, the [tex]\( y \)[/tex]-intercept of the line perpendicular to [tex]\( y = -\frac{3}{4} x + 5 \)[/tex] and passing through the point [tex]\((-3, -3)\)[/tex] is [tex]\( 1 \)[/tex], which corresponds to the option [tex]\(\boxed{1}\)[/tex].