\[\boxed{\mathbf{3.}\mathbf{250}}\]
Пояснение.
Решение.
\[\textbf{а)}\ 43a + 36a + 64a + 57a =\]
\[= (43 + 57) \cdot a + (36 + 64) \cdot a =\]
\[= 100a + 100a = 200a\]
\[a = 56:\]
\[200a = 200 \cdot 56 = 11\ 200.\ \]
\[\textbf{б)}\ 134p - 68p - 34p =\]
\[= (134 - 34) \cdot p - 68p =\]
\[= 100p - 68p =\]
\[= (100 - 68) \cdot p = 32p\]
\[p = 12:\]
\[32p = 32 \cdot 12 = 32 \cdot (10 + 2) =\]
\[= 32 \cdot 10 + 32 \cdot 2 = 320 + 64 =\]
\[= 384.\]