<PRE><B>Question 390729</B>
The line passing through (x,4) and (4,-5) is perpendicular to a line with a slope of -7/3.
 What is the value of x?
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Find the slope of the line perpendicular to slope of -7/3 using: m1*m2 = -1
Let m1 = -7/3, find m2
{{{-7/3}}}*m2 = -1
m2 = {{{-3/7}}}*-1
m2 = {{{3/7}}}
:
Use the slope formula {{{(y2-y1)/(x2-x1)}}} = m2
Using the given values
{{{(-5-4)/(4-x)}}} = {{{3/7}}}
:
{{{(-9)/(4-x)}}} = {{{3/7}}}
Cross multiply
3(4-x) = -9*7
12 - 3x = -63
-3x = -63 - 12
-3x = -75
x = {{{(-75)/(-3)}}}
x = +25
:
:
Check this by finding the slope using x=25
{{{(-5-4)/(4-25)}}} = 
{{{(-9)/(-21)}}} = {{{3/7}}}</PRE>