Here is the equation: [tex]x+(x+3)=11[/tex] ⇒[tex]x+x+3=11[/tex]
You need to get "x" by itself so minus 3 from each side
[tex]x+x+3-3=11-3[/tex] ⇒ [tex]x+x=8[/tex] ⇒ [tex]2x=8[/tex]
Divide 8 by 2
[tex]8[/tex] ÷ [tex]2=4[/tex]
x=4
So each 4 is equivalent to 4
Lets check:
[tex]4+(4+3)=11[/tex] ⇒ [tex]4+4+3=11[/tex] ⇒ [tex]11=11[/tex]
So that means that Marcus practiced the piano for 4 hours and Donnel practiced for 7