\[\boxed{\text{103\ (103).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ (x - 1) + (12 - 7,5x) =\]
\[= (12 - 1) - (7,5x - x) =\]
\[= 11 - 6,5x\]
\[\textbf{б)}\ (2p + 1,9) - (7 - p) =\]
\[= (2p + p) - (7 - 1,9) =\]
\[= 3p - 5,1\]
\[\textbf{в)}\ (3 - 0,4a) - (10 - 0,8a) =\]
\[= (0,8a - 0,4a) - (10 - 3) =\]
\[= 0,4a - 7\]
\[\textbf{г)}\ b - (4 - 2b) + (3b - 1) =\]
\[= (b + 2b + 3b) - (4 + 1) =\]
\[= 6b - 5\ \]
\[\textbf{д)}\ y - (y + 4) + (y - 4) =\]
\[= (y - y + y) - (4 + 4) =\]
\[= y - 8\]
\[\textbf{е)}\ 4x - (1 - 2x) + (2x - 7) =\]
\[= (4x + 2x + 2x) - (7 + 1) =\]
\[= 8x - 8\]