document.write( "Question 227045: a line through (-9,-9) and a slope of -7 has a y-intercept at what? \n" ); document.write( "
Algebra.Com's Answer #168833 by algebrapro18(249)\"\" \"About 
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Their are 2 ways to solve this problem.
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\n" ); document.write( "\n" ); document.write( "Method 1. Using the slope-intercept formula of a line.
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\n" ); document.write( "\n" ); document.write( "We know that the equation of a line in slope interecept form is y=mx+b where m is the slope and b is the y intercept. Since we have the slope and a point we could plug those in and solve for b.
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\n" ); document.write( "\n" ); document.write( "y = mx+b
\n" ); document.write( "-9 = 7(-9)+b
\n" ); document.write( "-9 = -63+b
\n" ); document.write( "54 = b
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\n" ); document.write( "\n" ); document.write( "So we know the y-intercept is at 54.
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\n" ); document.write( "\n" ); document.write( "Method 2. Using the point slope formula.
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\n" ); document.write( "\n" ); document.write( "There is another equation that will give us the equation of a line. Its y-y1=m(x-x1). Where (x1,y1) is the given point and m is your slope.
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\n" ); document.write( "\n" ); document.write( "Plugging in the values we have we get:
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\n" ); document.write( "\n" ); document.write( "y-(-9) = 7(x-(-9))
\n" ); document.write( "y + 9 = 7(x+9)
\n" ); document.write( "y = 7x+63-9
\n" ); document.write( "y = 7x+54
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\n" ); document.write( "\n" ); document.write( "SO we know that the y-intercept is 54.
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\n" ); document.write( "\n" ); document.write( "Either method you use will get you the right answer. \n" ); document.write( "
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