a)
[tex]30 - (24 \div 6 + 20 \div 5) + 2 = [/tex]
[tex]30 - (4 + 4) + 2 = [/tex]
[tex]30 - 4 + 2 = [/tex]
[tex]26 + 2 = 28[/tex]
b)
[tex]14 + 3 \times (36 \div 4 - 28 \div 7) = [/tex]
[tex]14 + 3 \times (9 - 4) = [/tex]
[tex]14 + 3 \times 5 = [/tex]
[tex]14 + 15 = 29[/tex]
c)