document.write( "Question 668169: I have to solve this problem using the substitution method. 4x-y=6 and 9x-2y=16. I have no idea how to do this. \n" ); document.write( "
Algebra.Com's Answer #415399 by ankor@dixie-net.com(22740)\"\" \"About 
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4x - y = 6 and 9x - 2y = 16.
\n" ); document.write( "If I do my job right, you will know how to do the substitution method when I am done here
\n" ); document.write( ":
\n" ); document.write( "First we select which equation to use for substitution, try to choose the one
\n" ); document.write( "that has a variable with a coefficient of 1, makes it simpler
\n" ); document.write( ":
\n" ); document.write( "The 1st equation
\n" ); document.write( "4x - y = 6
\n" ); document.write( "Subtract 4x from both side
\n" ); document.write( "-y = -4x + 6
\n" ); document.write( "y has to be positive, multiply each term by -1
\n" ); document.write( "y = 4x - 6
\n" ); document.write( ":
\n" ); document.write( "The 2nd equation:
\n" ); document.write( "9x - 2y = 16
\n" ); document.write( "we know from the 1st equation that y = (4x-6),
\n" ); document.write( "replace y with (4x-6) in the above the above equation
\n" ); document.write( "9x - 2(4x-6) = 16
\n" ); document.write( "multiply what's inside the brackets by -2 and you have
\n" ); document.write( "9x - 8x + 12 = 16
\n" ); document.write( "subtract 12 from both sides, combine the x's
\n" ); document.write( "x = 16 - 12
\n" ); document.write( "x = 4
\n" ); document.write( ":
\n" ); document.write( "We can use y = (4x-6) to find y, replace x with 4
\n" ); document.write( "y = 4(4) - 6
\n" ); document.write( "y = 16 - 6
\n" ); document.write( "y = 10
\n" ); document.write( ":
\n" ); document.write( "Our solution: x = 4; y = 10
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check our solution in the original 2nd equation 9x - 2y = 16, replace x & y
\n" ); document.write( "9(4) - 2(10) = 16
\n" ); document.write( "36 - 20 = 16; confirms our solutions
\n" ); document.write( ":
\n" ); document.write( "If you still cannot get your mind around the substitution method, I suggest you
\n" ); document.write( "print this out and endeavor to understand each step, individually. it will be
\n" ); document.write( "time well spent. C \n" ); document.write( "
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