document.write( "Question 171331: I've asked for help several times and have not gotten a response, is there any specific reason why my questions are being ignored.\r
\n" ); document.write( "\n" ); document.write( "Write an equation fo the line passing through the given points.\r
\n" ); document.write( "\n" ); document.write( "(3,-12) and (-4,2)\r
\n" ); document.write( "\n" ); document.write( "Can someone be generous enough to help me
\n" ); document.write( " \n" ); document.write( "
Algebra.Com's Answer #126485 by gonzo(654)\"\" \"About 
You can put this solution on YOUR website!
i was going to quit but your plea struck a chord.
\n" ); document.write( "your problem:
\n" ); document.write( "you have two points:
\n" ); document.write( "(3,-12)
\n" ); document.write( "(-4,2)
\n" ); document.write( "with these two points you can find the equation for the line passing through them as follows:
\n" ); document.write( "-----
\n" ); document.write( "the slope intercept form of the equation for a line is y = m*x + b
\n" ); document.write( "m is the slope
\n" ); document.write( "b is the y-intercept (value of y when x = 0).
\n" ); document.write( "-----
\n" ); document.write( "your points are coordinates where the first point of the pair is the x coordinate and the second point of the pair is the y coordinate.
\n" ); document.write( "general form is (x,y).
\n" ); document.write( "-----
\n" ); document.write( "general formula for finding the slope is:
\n" ); document.write( "m = (y2-y1)/(x2-x1)
\n" ); document.write( "let x1 = 3 and y1 = -12
\n" ); document.write( "let x2 = -4 and y2 = 2
\n" ); document.write( "formula becomes:
\n" ); document.write( "m = (2-(-12))/((-4)-3)
\n" ); document.write( "simplify:
\n" ); document.write( "m = 14/(-7) = -2
\n" ); document.write( "-----
\n" ); document.write( "your slope is -2
\n" ); document.write( "y = m*x + b becomes:
\n" ); document.write( "y = -2*x + b
\n" ); document.write( "-----
\n" ); document.write( "now you have to find the y intercept.
\n" ); document.write( "-----
\n" ); document.write( "you need to take one of those points (either one will do) and substitute in the equation.
\n" ); document.write( "we'll take the first 1.
\n" ); document.write( "the equation:
\n" ); document.write( "y = -2*x + b
\n" ); document.write( "becomes:
\n" ); document.write( "-12 = -2*(3) + b
\n" ); document.write( "-12 = -6 + b
\n" ); document.write( "-6 = b
\n" ); document.write( "-----
\n" ); document.write( "if we used the second pair of points, we should have come up with the same answer.
\n" ); document.write( "let's try:
\n" ); document.write( "we'll now take the second 1.
\n" ); document.write( "the equation:
\n" ); document.write( "y = -2*x + b
\n" ); document.write( "becomes:
\n" ); document.write( "2 = -2*(-4) + b
\n" ); document.write( "2 = 8 + b
\n" ); document.write( "-6 = b
\n" ); document.write( "-----
\n" ); document.write( "b was -6 in both cases.
\n" ); document.write( "we have solved for b and the equation now becomes:
\n" ); document.write( "y = -2*x -6
\n" ); document.write( "-----
\n" ); document.write( "if this equation is good, then both points should make the equation true.
\n" ); document.write( "let's use the first pair of points (3,-12)
\n" ); document.write( "y = -2*x - 6
\n" ); document.write( "becomes:
\n" ); document.write( "-12 = -2*3 -6
\n" ); document.write( "-12 = -6 -6
\n" ); document.write( "-12 = -12
\n" ); document.write( "first pair proves equation true
\n" ); document.write( "-----
\n" ); document.write( "lets use the second pair of points (-4,2)
\n" ); document.write( "y = -2*x - 6
\n" ); document.write( "becomes:
\n" ); document.write( "2 = -2*-4 -6
\n" ); document.write( "2 = 8-6
\n" ); document.write( "2 = 2
\n" ); document.write( "second pair proves equation true
\n" ); document.write( "-----
\n" ); document.write( "equation is:
\n" ); document.write( "y = -2*x-6
\n" ); document.write( "-----
\n" ); document.write( "graph of this equation is shown below:
\n" ); document.write( "\"graph%28800%2C800%2C-10%2C10%2C-10%2C10%2C-2x-6%29\"
\n" ); document.write( "note the y intercept is -6 which is the value of b we solved for earlier.
\n" ); document.write( "in the equation y = -2*x - 6, if we make x = 0, then we get y = -6.
\n" ); document.write( "-----
\n" ); document.write( "note the x intercept is -3.
\n" ); document.write( "in the equation y = -2*x - 6, if we make y = 0, then we get:
\n" ); document.write( "0 = -2*x - 6
\n" ); document.write( "which becomes:
\n" ); document.write( "-2*x = 6
\n" ); document.write( "-x = 6/2 = 3
\n" ); document.write( "x = -3
\n" ); document.write( "-----
\n" ); document.write( "everything checks out and the graph is good.\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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