document.write( "Question 612769: what is the positive x-intercept of the quadratic function f(x)=x^2+2x-63 \n" ); document.write( "

Algebra.Com's Answer #385724 by Theo(13342) $\"\"$ $\"About$

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should be x = 7
\n" ); document.write( "factor the quadratic equation as follows:
\n" ); document.write( "(x-a)*(x+b) = 0
\n" ); document.write( "you want an a and a b such that b-a = 2
\n" ); document.write( "look at the factors of a*b that equal 63.
\n" ); document.write( "you get:
\n" ); document.write( "63*1
\n" ); document.write( "21*3
\n" ); document.write( "7*9
\n" ); document.write( "looks like 7 and 9 will do it because 9-7 = 2
\n" ); document.write( "set b = 9 and a = 7 and you get:
\n" ); document.write( "(x-7) * (x+9) = 0
\n" ); document.write( "results in x = 7 or x = -9
\n" ); document.write( "positive x-intercept is 7.
\n" ); document.write( "graph of the equation of x^2 + 2x - 63 confirms it as shown below:
\n" ); document.write( " $\"graph%28600%2C600%2C-10%2C10%2C-100%2C100%2Cx%5E2%2B2x-63%29\"$
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