a)
[tex]7 \times (2x - 1) = 35 \\ 14x - 7 = 35 \\ 14x = 35 + 7 \\ 14x = 42 \\ x = 42 \div 14 \\ x = 3[/tex]
b)
[tex]3(2x + 5) = 63 \\ 6x + 15 = 63 \\ 6x = 63 - 15 \\ 6x = 48 \\ x = 48 \div 6 \\ x = 8[/tex]
c)
[tex]6 \times (3x + 9) = - 72 \\ 18x + 54 = - 72 \\ 18x = - 72 - 54 \\ 18x = - 126 \\ x = -126 \div 18 \\ x = -7[/tex]