document.write( "Question 166492: please help me solve this problem.\r
\n" ); document.write( "\n" ); document.write( "the area of a triangle is 13.5 meters. Find the base and height of the retangle
\n" ); document.write( "if its height is 6 meters greaster than it's base. Use an equation and the formula area of a triangle =0.5(base)(height).
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Algebra.Com's Answer #122697 by gonzo(654)\"\" \"About 
You can put this solution on YOUR website!
A = (b*h)/2 (equation 1)
\n" ); document.write( "where A = area
\n" ); document.write( "b = base
\n" ); document.write( "h = height
\n" ); document.write( "-----
\n" ); document.write( "h = b+6 (given)
\n" ); document.write( "A = 13.5 (given)
\n" ); document.write( "equation 1 becomes:
\n" ); document.write( "A = [b*(b+6)]/2 = 13.5
\n" ); document.write( "which becomes:
\n" ); document.write( "[b*(b+6)]/2 = 13.5 (equation 2)
\n" ); document.write( "-----
\n" ); document.write( "multiply both sides of equation 2 by 2:
\n" ); document.write( "b*(b+6) = 27
\n" ); document.write( "simplify:
\n" ); document.write( "b^2 + 6*b = 27
\n" ); document.write( "complete the squares:
\n" ); document.write( "(b+3)^2 = 27 + 9 (explanation for this down below after the answer)
\n" ); document.write( "simplify:
\n" ); document.write( "(b+3)^2 = 36
\n" ); document.write( "take square root of both sides:
\n" ); document.write( "b+3 = +/- 6
\n" ); document.write( "subtract 3 from both sides:
\n" ); document.write( "b = +/- 6 - 3
\n" ); document.write( "b becomes either:
\n" ); document.write( "6-3 = 3
\n" ); document.write( "or:
\n" ); document.write( "-6-3 = -9
\n" ); document.write( "-----
\n" ); document.write( "since b can't be negative, answer has to be:
\n" ); document.write( "b = 3
\n" ); document.write( "-----
\n" ); document.write( "since h = b+6, then:
\n" ); document.write( "h = 9
\n" ); document.write( "-----
\n" ); document.write( "you have:
\n" ); document.write( "b = 3
\n" ); document.write( "h = 9
\n" ); document.write( "A = 13.5 (given)
\n" ); document.write( "-----
\n" ); document.write( "substitute in equation 1:
\n" ); document.write( "A = (b*h)/2 (equation 1)
\n" ); document.write( "A = (3*9)/2 = 13.5
\n" ); document.write( "A = 27/2 = 13.5
\n" ); document.write( "A = 13.5 = 13.5
\n" ); document.write( "-----
\n" ); document.write( "values for b and h prove out.
\n" ); document.write( "equation is good.
\n" ); document.write( "b = 3
\n" ); document.write( "h = 9
\n" ); document.write( "-----
\n" ); document.write( "explanation for completing the squares is shown below:
\n" ); document.write( "also shown below is the fact that you could have also solved this using the quadratic formula.
\n" ); document.write( "-----
\n" ); document.write( "in order to complete the squares of your equation:
\n" ); document.write( "b^2 + 6*b)
\n" ); document.write( "i took half of the 6 and turned the equation into:
\n" ); document.write( "(b+3)^2
\n" ); document.write( "if you multiply this out, you will get:
\n" ); document.write( "b^2 + 6*b + 9
\n" ); document.write( "there's an extra 9 in there.
\n" ); document.write( "in order to keep the equations in balance i had to add 9 to the other side of the equation.
\n" ); document.write( "that's why the equation went from:
\n" ); document.write( "b^2 + 6*b = 27
\n" ); document.write( "to:
\n" ); document.write( "(b+3)^2 = 27 + 9
\n" ); document.write( "the additional 9 on the right hand side of the equation kept them in balance because i added 9 to the left hand side by completing the squares.
\n" ); document.write( "-----
\n" ); document.write( "use of the quadratic formula instead.
\n" ); document.write( "-----
\n" ); document.write( "rather than completing the squares, you can also solve this equation using the quadratic formula.
\n" ); document.write( "the equation to solve was:
\n" ); document.write( "b^2 + 6*b = 27
\n" ); document.write( "subtract 27 from both sides of the equation:
\n" ); document.write( "b^2 + 6*b - 27 = 0
\n" ); document.write( "let x = b (this is necessary because general form of quadratic equation and quadratic formula use b for another purpose)
\n" ); document.write( "-----
\n" ); document.write( "formula becomes:
\n" ); document.write( "x^2 + 6*x - 27 = 0
\n" ); document.write( "general form of quadratic equation is:
\n" ); document.write( "a*x^2 + b*x + c = 0
\n" ); document.write( "the quadratic formula can be used to solve this quadratic equation.
\n" ); document.write( "general form of quadratic formula is: x = \"%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"
\n" ); document.write( "a = 1
\n" ); document.write( "b = 6
\n" ); document.write( "c = -27
\n" ); document.write( "-----
\n" ); document.write( "b^2 = 36
\n" ); document.write( "4*a*c = -108
\n" ); document.write( "2*a = 2
\n" ); document.write( "-----
\n" ); document.write( "quadratic formula becomes
\n" ); document.write( "x = \"%28-6+%2B-+sqrt%2836-%28-108%29%29%29%2F2\"
\n" ); document.write( "this becomes:
\n" ); document.write( "x = (-6 +/- 12)/2
\n" ); document.write( "which becomes
\n" ); document.write( "x = 6/2 = 3
\n" ); document.write( "or:
\n" ); document.write( "x = -18/2 = -9
\n" ); document.write( "-----
\n" ); document.write( "the answers are the same.
\n" ); document.write( "you could solve by completing the square or you could solve by quadratic formula, whichever is easiest for you.
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