document.write( "Question 421852: can u please help me solve this question?\r
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document.write( "1.The straight line y=3-4x does not intersect the curve y=5x^2-x+q.Find the range of values of q. \n" );
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Algebra.Com's Answer #294539 by Theo(13342)![]() ![]() You can put this solution on YOUR website! I've never seen a problem like this before, but I think I have a solution, although it may not be the preferred way of dealing with this type of problem.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If the equation of y = 5x^2 - x + q is to intersect with the line y = 3-4x, then to find the points of intersection, we would set y equal to 3-4x and solve for x.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "accordingly, we set 5x^2 - x + q = 3 - 4x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if we subtract 3 from both sides of the equation and we add 4x to both sides of the equation, we get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5x^2 + 3x - 3 + q = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we can rearrange the terms to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5x^2 + 3x - (q+3) = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the standard form of a quadratic equation is ax^2 + bx + c = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in our equation:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a = 5 \n" ); document.write( "b = 3 \n" ); document.write( "c = (q+3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we find the piece parts of the quadratic formula as follows:\r \n" ); document.write( "\n" ); document.write( "2a = 10 \n" ); document.write( "-b = -3 \n" ); document.write( "4ac = 4*5*(q-3) = 20q - 60 \n" ); document.write( "b^2 = 9 \n" ); document.write( "b^2 - 4ac = 9 - 20q + 60- = 69-20q \n" ); document.write( "the discriminant is equal to 69 - 20q \n" ); document.write( "in order for there to be real roots to this equation, the discriminant has to be >= 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "set 69-20q >= 0 and solve for q \n" ); document.write( "add 20q to both sides of this equation to get 69 >= 20q \n" ); document.write( "divide both sides of this equation by 20 to get 69/20 >= q \n" ); document.write( "commute this equation to get q <= 69/20 \n" ); document.write( "simplify this to get q <= 3.45\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if q <= 3.45, then we WILL get an intersection of the graph of the equation y = 3 - 4x with the graph of the equation y = 5x^2 - x + q\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "conversely, if q > 3.45, then we WILL NOT get an intersection of the graph of the equation y = 3 - 4x with the graph of the equation y = 5x^2 - x + q\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the following graph sets q equal to 3.45\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the following graph sets q equal to 4 which is greater than 3.45\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the following graph sets q equal to 3 which is less than 3.45\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you can see that when q <= 3.45, the 2 graphs intersect, and you can see that when q > 3.45, the 2 graphs do not intersect.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in order for there to be a real solution to the intersection of the graph of the 2 equations, the roots of the resulting quadratic equation had to be real.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in order for them to be real, the discriminant had to be >= 0.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that led to the solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |