document.write( "Question 386731: The sum of three number is 23 the first number is equal to twice the second number minus 7 the third number is equal to one more than the sum of the first and second numbers what is the first number
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Algebra.Com's Answer #275344 by gwendolyn(128)\"\" \"About 
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Let's assign variables to the three numbers.
\n" ); document.write( "let x=the first number
\n" ); document.write( "let y=the second number
\n" ); document.write( "let z=the third number
\n" ); document.write( "When all the numbers are added together, their total is 23. This can be expressed in an equation:
\n" ); document.write( "x+y+z=23
\n" ); document.write( "x is 2 times y minus 7, which can be said as:
\n" ); document.write( "x=2y-7
\n" ); document.write( "Finally, the question states that z is 1 plus x plus y. So:
\n" ); document.write( "z=1+x+y
\n" ); document.write( "We can substitute the values of x and y that we have from our second and third equations into our first equation:
\n" ); document.write( "x+y+z=23
\n" ); document.write( "2y-7+y+1+x+y=23
\n" ); document.write( "Next, we can simplify the equation:
\n" ); document.write( "2y-7+y+1+x+y=23
\n" ); document.write( "4y-6+x=23
\n" ); document.write( "4y+x=29
\n" ); document.write( "Then, we can substitute the value of x into the equation again:
\n" ); document.write( "4y+x=29
\n" ); document.write( "4y+2y-7=29
\n" ); document.write( "6y=36
\n" ); document.write( "Finally, we divide both sides by 6 to isolate the variable and find y's value:
\n" ); document.write( "y=6
\n" ); document.write( "We can then substitute y's value into the equation for x, which the question asked us to find.
\n" ); document.write( "x=2y-7
\n" ); document.write( "\"x=2%2A6-7\"
\n" ); document.write( "x=12-7
\n" ); document.write( "x=5
\n" ); document.write( "Therefore, the first number is 5. \n" ); document.write( "
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