1.
[tex]100 - 2 \times 2 \times 8 - (35 \div a + 15) \div 4 = 63 \\ 100 - 4 \times 8 - (35 \div a + 15) \div 4 = 63 \\ 100 - 32 - (35 \div a + 15) \div 4 = 63 \\ 68 - (35 \div a + 15) \div 4 = 63 \\ (35 \div a + 15) \div 4 = 68 - 63 \\ (35 \div a + 15) \div 4 = 5 \\ 35 \div a + 15 = 5 \times 4 \\ 35 \div a + 15 = 20 \\ 35 \div a = 20 - 15 \\ 35 \div a = 5 \\ a = 35 \div 5 \\ a = 7[/tex]
2.
[tex]({352 - (29 \times 5 + 5 \times a \div 5)}) \div 2 + 56 \times 13 = 796 \\ (352 - (145 + 5 \times a \div 5)) \div 2 + 728 = 796 \\ (352 - (145 + 5 \times a \div 5)) \div 2 = 796 - 728 \\ (352 - (145 + 5 \times a \div 5)) \div 2 = 68 \\ 352 - (145 + 5 \times a \div 5)= 68 \times 2 \\ 352 - (145 + 5 \times a \div 5) = 136 \\ 145 + 5 \times a \div 5 = 352 - 136 \\ 145 + 5 \times a \div 5 = 216 \\ 5 \times a \div 5 = 216 - 145 \\ 5 \times a \div 5 = 71 \\ 5 \times a = 71 \times 5 \\ 5 \times a = 355 \\ a = 355 \div 5 \\ a = 71[/tex]
3.
[tex]2 \times 50 + 35 \times a = 170 \\ 100 + 35 \times a = 170 \\ 35 \times a = 170 - 100 \\ 35 \times a = 70 \\ a = 70 \div 35 \\ a = 2[/tex]
4.
[tex]m \times 3 + 27 \times 9 = 255 \\ m \times 3 + 243 = 255 \\ m \times 3 = 255 - 243 \\ m \times 3 = 12 \\ m = 12 \div 3 \\ m = 4[/tex]
