document.write( "Question 35125: I need to find the intercept point of y=3x+8 and 4x+2y=6. If you can find the answer, would you explain it to me? I also have a few more to do and I need to understand how to do it. \n" ); document.write( "
Algebra.Com's Answer #21338 by longjonsilver(2297) You can put this solution on YOUR website! each is just a straight line, so if they cross, will be equal at that one point...the solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "As to how to do it: at that one point, the x,y values in both equation are the same eg at x=2, then y will be whatever, but both equations will give the same answer...the point is the same on both lines.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "OK, i have laboured the point enough. Method: \n" ); document.write( "y=3x+8 and 4x+2y=6 \n" ); document.write( "--> 2y=6x+16 is the first equation scalled up by factor of 2. Why did i do that? Well, now both equations have a \"2y\" term, so i can put one version into the other equation and just have an equation in \"x\", so i can solve that:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "sub 6x+16 in place of 2y in 4x+2y=6\r \n" ); document.write( "\n" ); document.write( "--> 4x+(6x+16)=6 \n" ); document.write( "4x+6x+16=6 \n" ); document.write( "10x+16=6 \n" ); document.write( "10x=-10 \n" ); document.write( "x=-10/10 \n" ); document.write( "--> x=-1\r \n" ); document.write( "\n" ); document.write( "and so from y=3x+8 (or the other one, it doesn't matter: i just picked the simplest one to work with) and knowing that x=-1, we get\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y=3(-1)+8 \n" ); document.write( "y=-3+8 \n" ); document.write( "y=5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the solution is x=-1, y=5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "CHECK other equation: \n" ); document.write( "4x+2y=6 \n" ); document.write( "4(-1)+2(5) \n" ); document.write( "-4+10 \n" ); document.write( "6 --> which is what the equation does equal, so we KNOW we have the correct answer.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Move on to next question, happy that you KNOW it is correct :-)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "jon. \n" ); document.write( " |