document.write( "Question 399219: I don't understand how to solve this equation $\"+x%5E2-4x%2B40=0+\"$ \n" ); document.write( "

Algebra.Com's Answer #282698 by richard1234(7193) $\"\"$ $\"About$

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Use the quadratic formula, which says that the roots of a polynomial in the form $\"ax%5E2+%2B+bx+%2B+c\"$ are $\"%28-b+%2B-+sqrt%28b%5E2+-+4ac%29%29%2F2a\"$ . Here, $\"a+=+1\"$ , $\"b+=+-4\"$ , $\"c+=+40\"$ so just replace each value and do the arithmetic. \n" ); document.write( "

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