document.write( "Question 1120951: state the number of solutions for the linear system of equations 27x=3y+78 3y=90-6x \n" ); document.write( "
Algebra.Com's Answer #736651 by Theo(13342)![]() ![]() You can put this solution on YOUR website! place these equations in slope intercept form.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "27x = 3y + 78 is the first equation. \n" ); document.write( "subtract 78 from both sides to get 27x - 78 = 3y \n" ); document.write( "solve for y to get y = 27x / 3 - 78/3 \n" ); document.write( "simplify to get y = 9x - 26\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3y = 90 - 6x \n" ); document.write( "rearrange the terms in descending order of degree tp get 3y = -6x + 90 \n" ); document.write( "divide both side by 3 to get y = -6/3 * x + 90/3 \n" ); document.write( "simplify to get y = -2x + 30\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "they are now both in slope intercept form of y = mx + b where m is the slope and b is the y-intercept.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the slopes are the same and the y-intercepts are the same, the lines are identical and you have an infinite number of possible solutions.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the slopes are the same and the y-intercepts are different, the lines are parallel and you have no possible solutions.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the slopes are not the same, the lines are not identical or parallel and you have one possible solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "these lines do not have the same slope and you therefore have one possible solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i graphed both equations and the graph shows one possible solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the red line is caused by the first equation after it have been placed in slope intercept form.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the blue line is caused by the second equation after it has been placed in slope intercept form.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the graph shows one solution at the coordinate point of (5.091,19.818)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that means x = 5.091 and y = 19.818 is the one common solution to both equations.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i solved them algebraically and this is what i got.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "start with:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "27x = 3y + 78 \n" ); document.write( "3y = 90 - 6x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for 3y in both equations to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3y = 27x - 78 \n" ); document.write( "3y = -6x + 90\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract the second equation from the first to get 0 = 33x - 168\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "add 168 to both sides of the equatino to get 168 = 33x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for x to get x = 168 / 33 = 5.090909091\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for y in either original equation to get y = 19.81818182\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "round to 3 decimal places and you get x = 5.091 and y = 19.818 as shown on the graph.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's the graph.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "there is only one solution for the system of these two equations.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |