Question 33544
4 shelves and 2 sides
shelf 1 = x
shelf 2 = x
shelf 3 = x
shelf 4 = x
side 1 = x + 2.5
side 2 = x + 2.5
total lumber = 26
X or W ... either variable works


{{{ x + x + x + x + (x + 2.5) + (x + 2.5) = 26 }}}
{{{ 4x + 2(x+2.5) = 26 }}}
YES .. you set it up right.


SOLVE:
{{{ 4x + 2(x+2.5) = 26 }}}
{{{ 4x + 2x + 5 = 26 }}}
{{{ 6x + 5 = 26 }}}
{{{ 6x = 21 }}}
{{{ x = 21/6 }}}


CHECK:
{{{ 4x + 2(x+2.5) = 26 }}}
{{{ 4(21/6) + 2((21/6)+2.5) = 26 }}}
change the 2.5 to 5/2
{{{ 4(21/6) + 2((21/6)+(5/2)) = 26 }}}
Find common denominators
{{{ 4(21/6) + 2((21/6)+(15/6)) = 26 }}}
Add the fractions
{{{ 4(21/6) + 2(36/6) = 26 }}}
Multiply
{{{ (84/6) + (72/6) = 26 }}}
Add
{{{ 156/6 = 26 }}}
{{{ 26 = 26 }}}
YES!!!