SOLUTION: 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 i
Algebra ->
Sequences-and-series
-> SOLUTION: 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 i
Log On
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
You can put this solution on YOUR website! Let's assign variables to the three numbers.
let x=the first number
let y=the second number
let z=the third number
When all the numbers are added together, their total is 23. This can be expressed in an equation:
x+y+z=23
x is 2 times y minus 7, which can be said as:
x=2y-7
Finally, the question states that z is 1 plus x plus y. So:
z=1+x+y
We can substitute the values of x and y that we have from our second and third equations into our first equation:
x+y+z=23
2y-7+y+1+x+y=23
Next, we can simplify the equation:
2y-7+y+1+x+y=23
4y-6+x=23
4y+x=29
Then, we can substitute the value of x into the equation again:
4y+x=29
4y+2y-7=29
6y=36
Finally, we divide both sides by 6 to isolate the variable and find y's value:
y=6
We can then substitute y's value into the equation for x, which the question asked us to find.
x=2y-7
x=12-7
x=5
Therefore, the first number is 5.
