Greetings!
"The sum of twice a number and 13 is 75."...
Let's translate this into an equation:
[tex]2x+13=75[/tex]
Solve for x:
Add -13 to both sides.
[tex](2x+13)+(-13)=(75)+(-13)[/tex]
Simplify.
[tex]2x=62[/tex]
Divide both sides by 2.
[tex](2x)/2=(62)/2[/tex]
Simplify.
[tex]x=31[/tex]
The variable is equal to 31.
Hope this helps.
-Benjamin