Question 983223
Instead of doing your problem for you, I'll do one exactly like it in every
detail so you can do yours yourself using this as a model. The problem I
will do is this
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The slope of the line passing through P(2,6) and Q(x,10) is -4/7. What is the value of x?
<pre>
Use the slope-intercept form:

{{{y-y[1]=m(x-x[1])}}}

Wehere {{{x[1]=2}}}, {{{y[1]=6}}}, {{{m=-4/7}}}

{{{y-6=expr(-4/7)(x-2)}}}

Now we substitute y=10

{{{10-6=expr(-4/7)(x-2)}}}

{{{4=expr(-4/7)(x-2)}}}

Multiply both sides by 7

{{{7*4=7*expr(-4/7)(x-2)}}}

{{{28=cross(7)*expr(-4/cross(7))(x-2)}}}

{{{28=-4(x-2)}}}

{{{28=-4x+8}}}

{{{20=-4x}}}

{{{-5=x}}}

Answer: -5.

Now do yours exactly the same way.

Edwin</pre>