.
The equation, which is the Math translation of the condition, is THIS :
x + 3*(x+3) = 2*((x+1) + (x+2) + (x+4)) - 39.
Simplify and solve it.
Can you do it on your own ?
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If you have difficulties in solving simple linear equations, look into the lesson
- HOW TO solve a linear equation
in this site.
Learn the subject from there.