Ответ:

вот ответ на 9 вопросссс

[tex]\displaystyle\bf\\9)\\\\(-3m+4y)^{2} -(-5y+3m)(3m+5y)+24my=\\\\=(4y-3m)^{2} -(3m-5y)(3m+5y)+24my=\\\\=(4y)^{2} -2\cdot 4y\cdot 3m+(3m)^{2} -\Big[(3m)^{2} -(5y)^{2} \Big]+24my=\\\\=16y^{2}-24my+9m^{2} -9m^{2} +25y^{2} +24my=\\\\=(16y^{2} +25y^{2} )+\underbrace{(24my-24my)}_{0}+\underbrace{(9m^{2} -9m^{2} )}_{0}=41y^{2}[/tex]

[tex]\displaystyle\bf\\10)\\\\(x+7)^{2} -(x-8)^{2} =-15\\\\x^{2}+2\cdot x\cdot 7+7^{2} -(x^{2} -2\cdot x\cdot 8+8^{2} )=-15\\\\x^{2} +14x+49-x^{2} +16x-64=-15\\\\30x-15=-15\\\\30x=-15+15\\\\30x=0\\\\\boxed{x=0}[/tex]