a)
[tex]7x - 11 = 10 \\ 7x = 21 | \div 7 \\ x = 3[/tex]
[tex]7 \times 3 - 11 = 10 \\ 21 - 11 = 10 \\ L = P[/tex]
b)
[tex] \frac{1}{2} x + 6 = 13 \\ \frac{1}{2} x = 7 | \times 2 \\ x = 14[/tex]
[tex] \frac{1}{2} \times 14 + 6 = 13 \\ 7 + 6 = 13 \\
L = P[/tex]
c)
[tex]5x + 21 = 46 \\ 5x = 25 | \div 5 \\ x = 5[/tex]
[tex]5 \times 5 + 21 = 46 \\ 25 + 21 = 46 \\
L = P[/tex]
