Question

умоляю помогите очень надо!​

Answer 1

Ответ:

$7m(m ^ { 3 } -8m ^ { 2 } +9) =7m ^4-56m ^3 +63m\\ (x-2)(2x+3) =2x ^2+3x-4x-6=2x ^2-x-6\\ (3m-4n)(5m+8n) =15m ^2+24mn-20mn-32n ^2=15m ^2 +4mn-32n ^2\\ ( y+3) ( { y }^{ 2 } +y-6) =y ^3+4y ^2-3y-18$

$12ab-18b ^ { 2 } =6b(2a-3b)\\ 21x ^ { 7 } -7x ^ { 4 } =7x ^4 (3x ^3-1)\\ 8x-8y+ax-ay =(a+8)(x-y)$

$2c(3c-7)-(c-1)(c+4) =6c ^2-14c-(c-1)(c+4)=6c ^2-14c-c ^2-3c+4=5c ^2-17c+4$

$\dfrac{ 4x-1 }{ 9 } - \dfrac{ x+2 }{ 6 } =2 |*18\\2(4x-1)-3(x+2)=36\\8x-2-3x-6=36\\5x-8=36\\5x=44\\x=\dfrac{44}{5} =8\dfrac{4}{5}$

$(3x-5)(2x+7)=(3x+1)(2x-3)+4x \\6x ^2+11x-35=(3x+1)(2x-3)+4x\\6x ^2+11x-35=6x ^2-7x-3+4x\\11x-35=-3x-3\\14x-35=-3\\14x=32\\x=\dfrac{32}{14} \\x=2\dfrac{2}{7}$

$14xy-2y+7x-1 =(7x-1)(2y+1)\\ (7 * \dfrac{ 8 }{ 7 } -1)( 2*(- \dfrac{ 6 }{ 10 } )+1) =7*((-\dfrac{6}{5} )+1)=7(-\dfrac{6}{5} +\dfrac{5}{5})=7*-\dfrac{1}{5}=-\dfrac{7}{5}=-1\dfrac{2}{5}$

$81 ^ { 5 } -27 ^ { 6 } = (3 ^ { 4 } ) ^ { 5 } -(3 ^ { 3 } ) ^ { 6 } =3 ^ { 20 } -3 ^ { 18 } =3 ^ { 18 } (3 ^ { 2 } -1)=3 ^ { 18 } (9-1)=3 ^ { 18 } * 8$

$x ^ { 2 } -12x+20 \\\sqrt{D} =\sqrt{144-4*1*20} =8\\x_{1} =\dfrac{12-8}{2} =2\\x_{2} =\dfrac{12+8}{2} =10\\ x ^ { 2 } -12x+20=(x-10)(x-2)$

Объяснение: