document.write( "Question 597910: in the formula shown here:
\n" ); document.write( "http://www.algebra.com/cgi-bin/plot-formula.mpl?expression=x+=+%28-b+%2B-+sqrt%28+d+%29%29%2F2a&x=0003
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\n" ); document.write( "(note: this is the quadratic formula)
\n" ); document.write( "I do not understand what the little box means in the equation. (in between the 2 and a.) Please explain! and it will also help to explain the whole thing, as I don't really understand all the signs, as I haven't learnt any of it before...thanks in advance:) \n" ); document.write( "
Algebra.Com's Answer #378415 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
Depending on how much you've learned of algebra so far, this could be a little confusing or very confusing, but here it goes.
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\n" ); document.write( "THE SYMBOLS FOR MULTIPLICATION:
\n" ); document.write( "At the bottom of the formula, between the 2 and the a , there is symbol called a middle dot.
\n" ); document.write( "That is a symbol used in algebra to mean multiplied by. The expression \"2%2Aa\" means 2 times a.
\n" ); document.write( "In algebra, the letter x is used a lot. The old X multiplication sign that is used in third grade looks too much like the letter x. That old X symbol could cause confusion, so it is not used.
\n" ); document.write( "Sometimes a middle dot is used to indicate multiplication, as in
\n" ); document.write( "\"3%2A5=15\" or \"2%2Aa\".
\n" ); document.write( "If there is no room for confusion, the middle dot can be skipped, so we are allowed to write \"2a\" instead of \"2%2Aa\".
\n" ); document.write( "To make matters a little more confusing, the asterisk is used as a middle dot when typing a middle dot symbol is difficult or impossible. So you may see 2*a instead of \"2a\" or \"2%2Aa\".
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\n" ); document.write( "THE QUADRATIC FORMULA:
\n" ); document.write( "The quadratic formula is used to find solutions to quadratic equations like
\n" ); document.write( "\"15x%5E2-14x-8=0\".
\n" ); document.write( "All quadratic equations can be represented with the general equation
\n" ); document.write( "\"ax%5E2%2Bbx%2Bc=0\" where a, b, and c represent the numbers in the equation.
\n" ); document.write( "For \"15x%5E2-14x-8=0\", a is 15, b is -14, and c is -8.
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\n" ); document.write( "Some quadratic equations have one or two real solutions. For other quadratic equations, there is no real number that could be a solution. It all depends on the value of an expression called the discriminant. In the formula you are asking about, the letter d represents the discriminant.
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\n" ); document.write( "The discriminant is the expression
\n" ); document.write( "\"b%5E2-4ac\" The 4, a, and c are multiplied together.
\n" ); document.write( "For \"15x%5E2-14x-8=0\", the discriminant is
\n" ); document.write( "\"%28-14%29%5E2-4%2A15%2A%28-8%29=196%2B480=676\"\r
\n" ); document.write( "\n" ); document.write( "If the discriminant is positive (as for the equation \"15x%5E2-14x-8=0\", with \"d=676\" for a discriminant), there are two distinct (meaning different) real solutions. They can be calculated using the formula
\n" ); document.write( "\"x=%28-b+%2B-+sqrt%28d%29%29%2F2a\"
\n" ); document.write( "For \"15x%5E2-14x-8=0\", it would be
\n" ); document.write( "\"x=%28-%28-14%29+%2B-+sqrt%28676%29%29%2F%282%2A15%29=%2814+%2B-+26%29%2F30\"
\n" ); document.write( "One solution is
\n" ); document.write( "\"x=%2814+%2B+26%29%2F30=40%2F30=4%2F3\".
\n" ); document.write( "The other is
\n" ); document.write( "\"x=%2814+-+26%29%2F30=-12%2F30=-2%2F5\". \n" ); document.write( "
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