document.write( "Question 477556: A square has an area of x^2 + 6x + 9 find the length of a side. Make a sketch of the square Please help \n" ); document.write( "
Algebra.Com's Answer #327296 by Theo(13342)![]() ![]() You can put this solution on YOUR website! the area of a square is equal to s*s = s^2 \n" ); document.write( "s = 1 side of the square. \n" ); document.write( "the area of the square is equal to x^2 + 6x + 9 \n" ); document.write( "this means that s^2 = x^2 + 6x + 9 \n" ); document.write( "this means that s = sqrt(x^2 + 6x + 9) \n" ); document.write( "it just so happens that x^2 + 6x + 9 is a perfect square. \n" ); document.write( "it is equal to (x+3)^2 \n" ); document.write( "this means that s^2 = (x+3)^2 which means that: \n" ); document.write( "sqrt(s^2) = +/- sqrt(x+3)^2 which means that: \n" ); document.write( "s = +/- (x+3) \n" ); document.write( "if s = + (x+3) then: \n" ); document.write( "s = x + 3 \n" ); document.write( "if s = -(x+3) then: \n" ); document.write( "s = -x - 3 \n" ); document.write( "now s has to be > 0. \n" ); document.write( "this means that: \n" ); document.write( "x+3 > 0 which means that x > -3 \n" ); document.write( "this also means that: \n" ); document.write( "-x-3 > 0 which means that x < -2 \n" ); document.write( "this means that x can be any real number except -3. \n" ); document.write( "when x is equal to -3, s is equal to 0 and the area of the square is equal to 0 which means that you don't have a square of any magnitude. \n" ); document.write( "the length of each side of your square is dependent on the value of x. \n" ); document.write( "a graph of the equation of x^2 + 6x + 9 is shown below: \n" ); document.write( "this graph shows the area of the square based on the value of x. \n" ); document.write( " \n" ); document.write( "regardless of the value of x, this graph will be positive which means the area of the square will be positive. \n" ); document.write( "this is everywhere except when x = -3. \n" ); document.write( "when x = -3, the area is zero which we already indicated is not valid. \n" ); document.write( "each side of your square, however, is not fixed to any one length. \n" ); document.write( "the length of each side is dependent on the value of x. \n" ); document.write( "a graph of the equation of y = +/- sqrt(x^2 + 6x + 9)}}} is shown below: \n" ); document.write( "this graph is showing the value of the side of the square based on the value of x. \n" ); document.write( " \n" ); document.write( "you can see that the length of each side will always be positive. \n" ); document.write( "it's low point is 0 when x = -3, which is disallowed. \n" ); document.write( "you asked me to draw your square. \n" ); document.write( "any square will do. \n" ); document.write( "just draw a rectangle which has all sides equal to each other. \n" ); document.write( "each side of this square will be equal to sqrt(x^2 + 6x + 9). \n" ); document.write( "x can be any value except -3. \n" ); document.write( "you can also show the value of each side of the square as follows: \n" ); document.write( "s = absolute value of (x+3). \n" ); document.write( "in formula terms, this looks like: \n" ); document.write( "s = |x+3| \n" ); document.write( "when (x+3) is positive, you get s = x + 3 \n" ); document.write( "when (x+3) is negative, you get s = -(x + 3) which becomes s = -x - 3. \n" ); document.write( "these are the same values we calculated above. \n" ); document.write( "as ugly as it might look, that's your answer. \n" ); document.write( "here's a picture of your square: \n" ); document.write( "the length of each side in the square is equal to |x+3|. \n" ); document.write( "this means each side in the square is equal to the absolute value of (x+3). \n" ); document.write( " ![]() \n" ); document.write( "an example: \n" ); document.write( "let x = -5. \n" ); document.write( "each side of your square is equal to |-5+3| which is equal to |-2| which is equal to 2. \n" ); document.write( "the area of your square is equal to x^2 + 6x + 9 after you replace x with (-5) to get (-5)^2 + 6*(-5) + 9 which is equal to 25 - 30 + 9 which is equal to 4. \n" ); document.write( "since 2^4 = 4, the dimensions of each side and the area of the square confirm that the value of x = |-2| is good. \n" ); document.write( "s is equal to 2 \n" ); document.write( "s^2 is equal to 4\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |