[tex]3 \times 2 - 4 \times ( - 3) + 7 \times 3 - (1 + 3 \times 5) = \\ 3 \times 2 - 4 \times ( - 3) + 7 \times 3 -( 1 +15 ) = \\ 6 - ( - 12) + 21 - 16 = \\ 6 + 12 + 21 - 16 = \\ 18 + 21 - 16 = \\ 39 - 16 = \\ 23[/tex]
