Find the distance between the point (-3, -4) and line 2y = -3x + 6.
a. square root 13
b. 23
c. 14
d. 23 square root 13 over 13

Respuesta :

Answer:

a. square root 13

Step-by-step explanation:

We need to find the equation of the  perpendicular line to 2y= -3x+6 that passes through the given point (-3, -4) and then  find the intersect of the two lines and finally calculate the distance beteen this intersect and the point (-3,-4)

Be careful the algebra sadly is a bit messy but here we go:

2y = -3x + 6

y=    -3/2 + 3

The slope of the perpendicular line is the negative inverse of (-3/2) which is 2/3

The perpendicular equation passing through (-3,-4) has the equation:

y-(-4)/(x-(-3))  = 2/3

y +4 = 2/3*x +2

y = 2/3 * x - 2

Now have a system of 2 equations with two unknowns

which are

y= -3/2 *x + 3

y=  2/3 *x -2

solving -3/2 *x + 3 = 2/3 * x -2

x = 30/13

annd then substituting in any of the equations to get y

y= -18/39 = -6/13

then the distance is given by the square root of the difference of the x values squared + the difference of y values squared ( Pythagoream Theorem):

sqrt (( (30/13 -(-3))2 + ( -6/13 +4 )^2 ))

sqrt ( 9^2/13^2 + 46^2/13^2)

1/13 * square root of (81 + 46^2) = 1/13 sqrt(2197)  (2197 =13 to the cube)

therefore we have

= ((1/13)  * 13) * sqrt 13 =   sqrt 13

Answer:

Option D.

Step-by-step explanation:

The distance between a point  and a line  is

[tex]Distance=\dfrac{|Ax_1+By_1+C|}{\sqrt{A^2+B^2}}[/tex]

The given equation of line is

[tex]2y=-3x+6[/tex]

It can be rewritten as

[tex]3x+2y-6=0[/tex]

Using the above formula the distance between (-3,-4) and  is

[tex]Distance=\dfrac{|3(-3)+2(-4)-6|}{\sqrt{3^2+2^2}}[/tex]

[tex]Distance=\dfrac{|-9-8-6|}{\sqrt{9+4}}[/tex]

[tex]Distance=\dfrac{|-23|}{\sqrt{13}}[/tex]

[tex]Distance=\dfrac{23}{\sqrt{13}}[/tex]

Rationalize the expression.

[tex]Distance=\dfrac{23}{\sqrt{13}}\times \dfrac{\sqrt{13}}{\sqrt{13}}[/tex]

[tex]Distance=\dfrac{23\sqrt{13}}{\sqrt{13}}[/tex]

Therefore, the correct option is D.