Given that 2x  +  1  =  5, what is the value of (x  +  3)3?

The answer is:  " 125 " .

Given: " 2x + 1 = 5 " ; what is the value of:  " (x + 3) ³ " ?


Start with:  " 2x + 1 = 5 " ; and solve for "x" ?

        →  2x + 1 = 5 ;

Subtract "1" from EACH SIDE of the equation:

        →  2x + 1 − 1 = 5 − 1 ;

to get:
  
        →  2x  =  4  ;

Divide EACH SIDE of the equation by "2" ;  to isolate "x" on one side of the equation ; and to solve for "x" ;

            2x / 2 = 4 / 2  ;

            x = 2 .

Now, plug in "2" for "x" in the expression:

        →   " (x + 3)³  "  ;  and simplify the expression ;

        →    (2 + 3)³  =  5³  =  5 * 5 * 5 = 25 * 5  = 125 .

The answer is:  " 125 " .