Question

помогите прошу.............................................

Answer 1

1.

$\frac{12y}{5x {}^{3} } \times \frac{15x {}^{9} }{8y {}^{2} } = \frac{3}{5x {}^{3} } \times \frac{15x {}^{9 } }{2y} = 3 \times \frac{3x {}^{6} }{2y} = \frac{9x {}^{6} }{2y}$

2.

$\frac{7ab {}^{2} }{40c {}^{4} } \times 5ac = \frac{7ab {}^{2} }{8c {}^{3} } \times 5a = \frac{35a {}^{2} b {}^{2} }{8c {}^{3} }$