document.write( "Question 1127693: find the formula for an exponential function that passes through the two points given.
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Algebra.Com's Answer #744181 by MathLover1(20850)\"\" \"About 
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a) (-1,1/2) and (4,512)\r
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"-1\",\"1%2F2\") and (\"4\",\"512\")
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\n" ); document.write( " \"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: (\"x%5B1%5D\",\"y%5B1%5D\") is the first point (\"-1\",\"1%2F2\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"4\",\"512\"))
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\n" ); document.write( " \"m=%28512-1%2F2%29%2F%284--1%29\" Plug in \"y%5B2%5D=512\",\"y%5B1%5D=1%2F2\",\"x%5B2%5D=4\",\"x%5B1%5D=-1\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+%281023%2F2%29%2F%285%2F1%29\" Subtract (note: if you need help with subtracting or dividing fractions, check out this solver)
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\n" ); document.write( " \"m=1023%2F10\" Divide the fractions
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=1023%2F10\"
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\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:
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\n" ); document.write( " ------Point-Slope Formula------
\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and (\"x%5B1%5D\",\"y%5B1%5D\") is one of the given points
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\n" ); document.write( " So lets use the Point-Slope Formula to find the equation of the line
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\n" ); document.write( " \"y-1%2F2=%281023%2F10%29%28x--1%29\" Plug in \"m=1023%2F10\", \"x%5B1%5D=-1\", and \"y%5B1%5D=1%2F2\" (these values are given)
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\n" ); document.write( " \"y-1%2F2=%281023%2F10%29%28x%2B1%29\" Rewrite \"x--1\" as \"x%2B1\"
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\n" ); document.write( " \"y-1%2F2=%281023%2F10%29x%2B%281023%2F10%29%281%29\" Distribute \"1023%2F10\"
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\n" ); document.write( " \"y-1%2F2=%281023%2F10%29x%2B1023%2F10\" Multiply \"1023%2F10\" and \"1\" to get \"1023%2F10\"
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\n" ); document.write( " \"y=%281023%2F10%29x%2B1023%2F10%2B1%2F2\" Add \"1%2F2\" to both sides to isolate y
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\n" ); document.write( " \"y=%281023%2F10%29x%2B514%2F5\" Combine like terms \"1023%2F10\" and \"1%2F2\" to get \"514%2F5\" (note: if you need help with combining fractions, check out this solver)
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\n" ); document.write( " Answer:
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\n" ); document.write( " So the equation of the line which goes through the points (\"-1\",\"1%2F2\") and (\"4\",\"512\") is:\"y=%281023%2F10%29x%2B514%2F5\"
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\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=1023%2F10\" and the y-intercept is \"b=514%2F5\"
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\n" ); document.write( " Notice if we graph the equation \"y=%281023%2F10%29x%2B514%2F5\" and plot the points (\"-1\",\"1%2F2\") and (\"4\",\"512\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=%281023%2F10%29x%2B514%2F5\" through the points (\"-1\",\"1%2F2\") and (\"4\",\"512\")
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\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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\n" ); document.write( "\n" ); document.write( "here is better graph:\r
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\n" ); document.write( "\n" ); document.write( "b) (-1,7) and (3,4)\r
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"-1\",\"7\") and (\"3\",\"4\")
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\n" ); document.write( " \"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: (\"x%5B1%5D\",\"y%5B1%5D\") is the first point (\"-1\",\"7\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"3\",\"4\"))
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\n" ); document.write( " \"m=%284-7%29%2F%283--1%29\" Plug in \"y%5B2%5D=4\",\"y%5B1%5D=7\",\"x%5B2%5D=3\",\"x%5B1%5D=-1\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+-3%2F4\" Subtract the terms in the numerator \"4-7\" to get \"-3\". Subtract the terms in the denominator \"3--1\" to get \"4\"
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=-3%2F4\"
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\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:
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\n" ); document.write( " ------Point-Slope Formula------
\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and (\"x%5B1%5D\",\"y%5B1%5D\") is one of the given points
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\n" ); document.write( " So lets use the Point-Slope Formula to find the equation of the line
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\n" ); document.write( " \"y-7=%28-3%2F4%29%28x--1%29\" Plug in \"m=-3%2F4\", \"x%5B1%5D=-1\", and \"y%5B1%5D=7\" (these values are given)
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\n" ); document.write( " \"y-7=%28-3%2F4%29%28x%2B1%29\" Rewrite \"x--1\" as \"x%2B1\"
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\n" ); document.write( " \"y-7=%28-3%2F4%29x%2B%28-3%2F4%29%281%29\" Distribute \"-3%2F4\"
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\n" ); document.write( " \"y-7=%28-3%2F4%29x-3%2F4\" Multiply \"-3%2F4\" and \"1\" to get \"-3%2F4\"
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\n" ); document.write( " \"y=%28-3%2F4%29x-3%2F4%2B7\" Add \"7\" to both sides to isolate y
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\n" ); document.write( " \"y=%28-3%2F4%29x%2B25%2F4\" Combine like terms \"-3%2F4\" and \"7\" to get \"25%2F4\" (note: if you need help with combining fractions, check out this solver)
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\n" ); document.write( " Answer:
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\n" ); document.write( " So the equation of the line which goes through the points (\"-1\",\"7\") and (\"3\",\"4\") is:\"y=%28-3%2F4%29x%2B25%2F4\"
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\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=-3%2F4\" and the y-intercept is \"b=25%2F4\"
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\n" ); document.write( " Notice if we graph the equation \"y=%28-3%2F4%29x%2B25%2F4\" and plot the points (\"-1\",\"7\") and (\"3\",\"4\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=%28-3%2F4%29x%2B25%2F4\" through the points (\"-1\",\"7\") and (\"3\",\"4\")
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\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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