a)
[tex]x + 12 = 13 \\ x = 1[/tex]
b)
[tex]6 + x = 2 \\ x = - 4[/tex]
c)
[tex]x - 7 = 9 \\ x = 16[/tex]
d)
[tex]3.7 + x = 2 \\ x = - 1.7[/tex]
e)
[tex]2x = 14 \\ x = 7[/tex]
f)
[tex] \frac{1}{3} x = 12 | \times 3 \\ x = 36[/tex]
g)
[tex]x \div 3 = 9 | \times 3 \\ x = 27[/tex]
h)
[tex] \frac{x}{2} = 9 | \times 2 \\ x = 18[/tex]
