document.write( "Question 79579: I need to solve algebraically, then graph. Should I solve by elimination or substitution? Either way I'm running into a lot of mumbo jumbo. Your help and/or hints are greatly appreciated!
\n" ); document.write( "X^2 - 4Y^2 = 16
\n" ); document.write( "2Y - X = 2
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Algebra.Com's Answer #57120 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve this system of equations: I would use substitution.
\n" ); document.write( "1) $\"x%5E2-4y%5E2+=+16\"$
\n" ); document.write( "2) $\"2y-x+=+2\"$ Write this as:
\n" ); document.write( "2a) $\"2y+=+x%2B2\"$ Now square both sides. $\"4y%5E2+=+x%5E2%2B4x%2B4\"$ and substitute into equation 1).
\n" ); document.write( " $\"x%5E2-%28x%5E2%2B4x%2B4%29+=+16\"$ Remove the parentheses (Remember to change the signs of the terms inside the parentheses!)
\n" ); document.write( " $\"x%5E2-x%5E2-4x-4+=+16\"$ Simplify.
\n" ); document.write( " $\"-4x-4+=+16\"$ Add 4 to both sides.
\n" ); document.write( " $\"-4x+=+20\"$ Divide both sides by -4.
\n" ); document.write( " $\"x+=+-5\"$ Now substitute this into equation 2a) and solve for y.
\n" ); document.write( "2a) $\"2y+=+-5%2B2\"$
\n" ); document.write( " $\"2y+=+-3\"$ Divide both sides by 2.
\n" ); document.write( " $\"y+=+-3%2F2\"$
\n" ); document.write( "The solution is: (-5, -3/2)
\n" ); document.write( "Check:
\n" ); document.write( " $\"%28-5%29%5E2-4%28-3%2F2%29%5E2+=+25-4%289%2F4%29\"$ = $\"25-9+=+16\"$ \n" ); document.write( "

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