51 Упростите выражение и подчеркните его коэффициент: a) -\frac{5}{6}x ⋅ (-\frac{1}{5}y); б) \frac{4}{7}a ⋅ (-\frac{7}{8}a); в) \frac{9}{20}x ⋅ (-\frac{4}{9}z); г) \frac{5}{12}x ⋅ (-\frac{4}{15}y); д) \frac{3}{8}n ⋅ (-\frac{7}{6}b) ⋅ \frac{2}{7}z; e) \frac{5}{9}a ⋅ \frac{9}{20}b ⋅ 3z.

Ответ: a) 1/6xy; б) -1/2a^2; в) -1/5xz; г) -1/9xy; д) -1/8bnz; e) 3/4abz

1. a) -\frac{5}{6}x \(\cdot\) (-\frac{1}{5}y) = \frac{5}{6} \(\cdot\) \frac{1}{5} xy = \frac{1}{6}xy
2. б) \frac{4}{7}a \(\cdot\) (-\frac{7}{8}a) = -\frac{4}{7} \(\cdot\) \frac{7}{8} a^2 = -\frac{1}{2}a^2
3. в) \frac{9}{20}x \(\cdot\) (-\frac{4}{9}z) = -\frac{9}{20} \(\cdot\) \frac{4}{9} xz = -\frac{1}{5}xz
4. г) \frac{5}{12}x \(\cdot\) (-\frac{4}{15}y) = -\frac{5}{12} \(\cdot\) \frac{4}{15} xy = -\frac{1}{9}xy
5. д) \frac{3}{8}n \(\cdot\) (-\frac{7}{6}b) \(\cdot\) \frac{2}{7}z = -\frac{3}{8} \(\cdot\) \frac{7}{6} \(\cdot\) \frac{2}{7} bnz = -\frac{1}{8}bnz
6. e) \frac{5}{9}a \(\cdot\) \frac{9}{20}b \(\cdot\) 3z = \frac{5}{9} \(\cdot\) \frac{9}{20} \(\cdot\) 3 abz = \frac{3}{4}abz

Ответ: a) 1/6xy; б) -1/2a^2; в) -1/5xz; г) -1/9xy; д) -1/8bnz; e) 3/4abz