Question 1068458
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That's just a fancy way of asking this question:

What is the equation of the line that passes through the two points 
{{{(matrix(1,3,-1/2,",",-7))}}} and {{{(matrix(1,3,1,",",-3))}}},
then what is y when x = -3?

First use the slope formula:

{{{m}}}{{{""=""}}}{{{(y[2]-y[1])/(x[2]-x[1])}}}

{{{m}}}{{{""=""}}}{{{((-3)-(-7))/((1)-(-1/2))}}}

{{{m}}}{{{""=""}}}{{{(-3+7)/(1+1/2)}}}

{{{m}}}{{{""=""}}}{{{(-3+7)/(2/2+1/2)}}}

{{{m}}}{{{""=""}}}{{{4/(3/2)}}}

{{{m}}}{{{""=""}}}{{{4}}}{{{"÷"}}}{{{3/2}}}

{{{m}}}{{{""=""}}}{{{4}}}{{{""*""}}}{{{2/3}}}

{{{m}}}{{{""=""}}}{{{8/3}}}

Then substitute in the point-slope formula:

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

{{{y-(-7)}}}{{{""=""}}}{{{expr(8/3)(x-(-1/2)^"")}}}

{{{y+7}}}{{{""=""}}}{{{expr(8/3)(x+1/2)}}}

Multiply both sides through by 3

{{{3y+21}}}{{{""=""}}}{{{8(x+1/2)}}}

{{{3y+21}}}{{{""=""}}}{{{8x+4}}}

Solve for y

{{{3y}}}{{{""=""}}}{{{8x-17}}}

{{{y}}}{{{""=""}}}{{{expr(8/3)x-17/3}}}

Finally substitute f(x) for y:

{{{"f(x)"}}}{{{""=""}}}{{{expr(8/3)x-17/3}}}

Then substitute -3 for x:

{{{"f(-3)"}}}{{{""=""}}}{{{expr(8/3)(-3)-17/3}}}

{{{"f(-3)"}}}{{{""=""}}}{{{-8-17/3}}}


{{{"f(-3)"}}}{{{""=""}}}{{{-24/3-17/3}}}


{{{"f(-3)"}}}{{{""=""}}}{{{-41/3}}}

Edwin</pre></b></font>