document.write( "Question 116283: Can you help me with these questions? I did not get this out of a book, it was a handout. The question is: Find the x and y intercepts and then graph
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document.write( " x-y=2 , -x+4y=4 and y = -4x -4. I do not fully understand the question.
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document.write( "Any help on this is greatly appreciated. Can you explain it step by step, not leaving anything out , please.\r
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document.write( "Thankyou
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document.write( "Laurie \n" );
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Algebra.Com's Answer #84587 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! : \n" ); document.write( "I will try to be very detailed on the 1st one, hopefully by the time you get to the 2nd one you will have an idea what's going on. \n" ); document.write( ": \n" ); document.write( "Find the x and y intercepts and then graph \n" ); document.write( ": \n" ); document.write( "x - y = 2 \n" ); document.write( "First we want to put the equation in the \"y =\"; subtract x from both sides: \n" ); document.write( "-y = -x - 2 \n" ); document.write( "y has to be positive in this form, multiply equation by -1 and you have: \n" ); document.write( "y = x + 2 \n" ); document.write( ": \n" ); document.write( "The x intercept occurs when y = 0, therefore make y = 0 and solve for x: \n" ); document.write( "x + 2 = y \n" ); document.write( "x + 2 = 0 \n" ); document.write( "x = -2; this is the x intercept \n" ); document.write( ": \n" ); document.write( "The y intercept occurs when x = 0; substitute 0 for x in our equation, find y: \n" ); document.write( "y = x + 2 \n" ); document.write( "y = 0 + 2 \n" ); document.write( "y = +2; this is the y intercept \n" ); document.write( ": \n" ); document.write( "To graph this we need at least two x,y points, choose convenient values for x: \n" ); document.write( " let x = -3 and let x = +3 \n" ); document.write( ": \n" ); document.write( "Substitute -3 for x: \n" ); document.write( "y = x + 2 \n" ); document.write( "y = -3 + 2 \n" ); document.write( "y = -1 \n" ); document.write( "Plot x=-3, y=-1 on a standard +/-10 graph \n" ); document.write( ": \n" ); document.write( "2nd point: x = +3 \n" ); document.write( "y = x + 2 \n" ); document.write( "y = 3 + 2 \n" ); document.write( "y = +5 \n" ); document.write( "Plot x=3, y=5 on the same graph, join points with a straight line, this is the graph \n" ); document.write( ": \n" ); document.write( "Should look like this \n" ); document.write( " \n" ); document.write( "Note that it confirms are values for the x and y intercepts \n" ); document.write( "The graph crosses the vertical line where y=2, (the y intercept) \n" ); document.write( "The graph crossed the horizontal line where x = -2; (the x intercept) \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "-x + 4y = 4 \n" ); document.write( "Put equation into the y= form, add x to both sides \n" ); document.write( "4y = x + 4 \n" ); document.write( "y has to have a coefficient of 1, divide both sides by 4 and you have: \n" ); document.write( "y = \n" ); document.write( "y = .25x + 1 \n" ); document.write( ": \n" ); document.write( "The x intercept (y=0): \n" ); document.write( ".25x + 1 = y \n" ); document.write( ".25x + 1 = 0 \n" ); document.write( ".25x = -1 \n" ); document.write( "x has to have a coefficient of 1, multiply both sides by 4 and you have; \n" ); document.write( "x = -4; is the x intercept \n" ); document.write( ": \n" ); document.write( "The y intercept (x=0) \n" ); document.write( "y = .25x + 1 \n" ); document.write( "y = .25(0) = 1 \n" ); document.write( "y = 0 + 1 \n" ); document.write( "y = 1 is the y intercept \n" ); document.write( ": \n" ); document.write( "two x,y points, choose some convenient values for x: \n" ); document.write( " let x = -3 and let x = +3 \n" ); document.write( ": \n" ); document.write( "Substitute -3 for x: \n" ); document.write( "y = .25x + 1 \n" ); document.write( "y = .25(-3) + 1 \n" ); document.write( "y = -.75 + 1 \n" ); document.write( "y = +.25 \n" ); document.write( "Plot x=-3, y=+.25 \n" ); document.write( ": \n" ); document.write( "2nd point: x = +3 \n" ); document.write( "y = .25(3) + 1 \n" ); document.write( "y = .75 + 1 \n" ); document.write( "y = +1.75 \n" ); document.write( "Plot x=3, y=1.75 on the same graph, join points with a straight line, this is the graph. \n" ); document.write( ": \n" ); document.write( "Should look like this \n" ); document.write( " \n" ); document.write( "Note that it confirms are values for the x and y intercepts \n" ); document.write( "The graph crosses the vertical line where y=1, (the y intercept) \n" ); document.write( "The graph crossed the horizontal line where x = -4; (the x intercept) \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "y = -4x - 4 this one is already in the form we want it: \n" ); document.write( ": \n" ); document.write( "x intercept (y=0) \n" ); document.write( "-4x -4 = y \n" ); document.write( "-4x - 4 = 0 \n" ); document.write( "-4x = +4; added 4 to both sides: \n" ); document.write( "x = -1; divided both sides by -4 to make the coefficient of x a +1 \n" ); document.write( ": \n" ); document.write( "y intercept (x=0) \n" ); document.write( "y = -4(0) - 4 \n" ); document.write( "y = -4; \n" ); document.write( ": \n" ); document.write( "Graph this equation the same way, it is more convenient to use x = -2 and x = +1 \n" ); document.write( "This is to keep the points on a +/-10 xy graph. \n" ); document.write( "Substitute -2 for x: \n" ); document.write( "y = -4x - 4 \n" ); document.write( "y = -4(-2) - 4 \n" ); document.write( "y = +8 - 4 \n" ); document.write( "y = +4 \n" ); document.write( "Plot x=-2, y=+4 \n" ); document.write( ": \n" ); document.write( "2nd point: x = +1 \n" ); document.write( "y = -4(1) - 4 \n" ); document.write( "y = -4 - 4 \n" ); document.write( "y = -8 \n" ); document.write( "Plot x=1, y=-8 on the same graph, join points with a straight line, \n" ); document.write( ": \n" ); document.write( "Should look like this \n" ); document.write( " \n" ); document.write( "Note that it confirms are values for the x and y intercepts \n" ); document.write( "The graph crosses the vertical line where y=-4, (the y intercept) \n" ); document.write( "The graph crossed the horizontal line where x = -1; (the x intercept) \n" ); document.write( ": \n" ); document.write( "It tried to make things clear here, if you have any questions about this concept you can email me. A \n" ); document.write( ":\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |