document.write( "Question 555500: How can i find the y-intercept using x=0 in the quadratic y= 2x^-5x-3? do I use the formula -b/2a to find the vertex for x or y=ax^2+bx+c or both? I need very clear instructions for this because i simply don't understand, sorry. \n" ); document.write( "

Algebra.Com's Answer #361800 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
1) $\"y+=+2x%5E2-5x-3\"$
\n" ); document.write( "To find the y-intercept, simply replace every x in the equation with 0 and evaluate.
\n" ); document.write( " $\"y+=+2x%5E2-5x-3\"$ Substitute x = 0.
\n" ); document.write( " $\"y+=+2%280%29%5E2-5%280%29-3\"$
\n" ); document.write( " $\"y+=+-3\"$ The curve (a parabola) intercepts the y-axis at (0, -3).
\n" ); document.write( "2) To find the x-coordinate of the vertex, us $\"-b%2F2a\"$ where a = 2 and b = -5.
\n" ); document.write( " $\"x+=+-%28-5%29%2F2%282%29\"$ Evaluate.
\n" ); document.write( " $\"x+=+5%2F4\"$ or $\"x+=+1.25\"$
\n" ); document.write( "Look at the graph of this equation:
\n" ); document.write( " $\"graph%28400%2C400%2C-5%2C5%2C-10%2C5%2C2x%5E2-5x-3%29\"$ \n" ); document.write( "

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