Answer:
17
Step-by-step explanation:
What we have to realize is that RS + ST = RT. Since we know the value of all, let's substitute inside the equation.
[tex]23 - 2x + 9x - 5 = 39[/tex]
Now let's try and solve for x by isolating the variable on one side.
Combine like terms:
[tex]7x + 18 = 39[/tex]
Subtract 18 from both sides:
[tex]7x = 21[/tex]
Divide both sides by 7:
[tex]x = 3[/tex]
Now that we know the value of x, we can substitute it back into the equation for RS, [tex]23-2x[/tex].
[tex]23-2(3)\\\\23-6\\17[/tex]
Hope this helped!
