To solve this first combine like terms.
6d+4+5d-2d=58
6d+5d=11d
11d-2d=9d
9d+4=58
Then continue by subtracting 4 from both sides of the equation.
9d+4=58
9d+4-4=58-4
9d=54
Divide both sides by 9 to isolate d.
=

d=6
To check if this answer is true, substitute 6 back into the original equation.
6(6)+4+5(6)-2(6)=58
36+4+30-12=58
40+30-12=58
70-12=58
58=58