Question

Упростите выражения Алгебра 7 класс

Answer 1

Объяснение:

$1) (2x^{5} y^{7} )^{3} :(x^{14} y^{20} )- (3xy^{5} )^{3} : ( x^{2} y^{14} )=( 2 ^{3} \cdot(x^{5} )^{3} \cdot(y^{7} )^{3} ) :(x^{14} y^{20} )- \\\\-(3^{3} \cdot x^{3} \cdot(y^{5} )^{3} ): ( x^{2} y^{14} )=8x^{15} y^{21} :(x^{14} y^{20} )-27x^{3} y^{15} : ( x^{2} y^{14} )= \\\\=\dfrac{8x^{15} y^{21}}{x^{14} y^{20}} - \dfrac{27x^{3} y^{15}}{ x^{2} y^{14} } =8xy-27xy= -19xy$

$2) (-3a^{4} b^{5} )^{2} \cdot (-2a^{2} b^{3} )^{3} : (-72a^{6} b^{9} )^{2} +a^{2}b =( (-3) ^{2} \cdot(a^{4} )^{2} \cdot(b^{5} )^{2} ) \cdot\\\\ (-2) ^{3} \cdot (a^{2} )^{3} \cdot(b^{3} )^{3} :((-72) ^{2} \cdot( a^{6} )^{2} \cdot( b^{9} )^{2} )+a^{2} b=\\\\9a^{8} b^{10} \cdot (-8a^{6} b^{9}) : (8^{2} \cdot9^{2} a^{12} b^{18} )+a^{2}b =\dfrac{9a^{8} b^{10} \cdot (-8a^{6} b^{9})}{8^{2} \cdot9^{2} a^{12} b^{18} } +a^{2}b =$

$=- \dfrac{9\cdot 8a^{14} b^{19} }{8^{2} \cdot9^{2} a^{12} b^{18} } +a^{2}b =-\dfrac{1}{72}a^{2} b +a^{2}b = -\dfrac{1}{72}a^{2} b +\dfrac{72}{72} a^{2}b = \dfrac{71}{72} a^{2}b .$