document.write( "Question 535652: I honestly have no idea what toopic this question would fall under... Solve this system of equations using substitution. Put your answer in ordered pair form, (x, y). x + 2y = 7 and 2x + y = 8 I can't figure out how to do it. I've tried to many times, but I can't figure it out. Can you please help me? \n" ); document.write( "
Algebra.Com's Answer #351998 by ankor@dixie-net.com(22740)\"\" \"About 
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Solve this system of equations using substitution. Put your answer in ordered pair form, (x, y).
\n" ); document.write( " x + 2y = 7
\n" ); document.write( " 2x + y = 8
\n" ); document.write( "we can use the 2nd equation for substitution
\n" ); document.write( "2x + y = 8
\n" ); document.write( "Subtract 2x from both sides
\n" ); document.write( "y = -2x + 8
\n" ); document.write( ":
\n" ); document.write( "Now we can substitute (-2x+8) for y in the 1st equation
\n" ); document.write( "x + 2y = 7
\n" ); document.write( "x + 2(-2x+8) = 7
\n" ); document.write( "x - 4x + 16 = 7
\n" ); document.write( "subtract 16 from both sides
\n" ); document.write( "x - 4x = 7 - 16
\n" ); document.write( "do the math
\n" ); document.write( "-3x = -9
\n" ); document.write( "x has to be positive, multiply both sides by -1, this changes the signs
\n" ); document.write( "3x = 9
\n" ); document.write( "divide both sides by 3
\n" ); document.write( "x = 9/3
\n" ); document.write( "x = 3
\n" ); document.write( ":
\n" ); document.write( "We can use the equation y =-2x+8, to find y, replace x with 3
\n" ); document.write( "y = -2(3) + 8
\n" ); document.write( "y = -6 + 8
\n" ); document.write( "y = 2
\n" ); document.write( ":
\n" ); document.write( "the x,y form (3,2)
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check our solutions in the 1st equation
\n" ); document.write( "x + 2y = 7
\n" ); document.write( "replace x and y with our solutions
\n" ); document.write( "3 + 2(2) = 7
\n" ); document.write( "3 + 4 = 7, confirms our solution
\n" ); document.write( ";
\n" ); document.write( "Are you understanding this better now, any questions? \n" ); document.write( "
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