First diagram:
Sum of the three parts is equal to 9: x+x+x is 9 or three times x is 9
Equations:
[tex]\begin{gathered} 3\cdot x=9 \\ 9=3\cdot x \\ x+x+x=9 \end{gathered}[/tex]
Also you can write the equation 3*x=9 as follow by solving x:
[tex]x=9\div3[/tex]
Second diagram:
Sum of the two parts is equal to 9: x+3 = 9
Equations:
[tex]\begin{gathered} x+3=9 \\ 3+x=9 \end{gathered}[/tex]
Solving x you can write the equation:
[tex]x=9-3[/tex]
