Question

задание за 100 балов​

Answer 1

1) х=1.5±√(2.25+54)=1.5±7.5; х=9; х=-6

2)  х=(7±√(49-24))/4=(7±5)/4; х=3; х=0.5

3)х=(9±√(81-32)/4=(9±7)/4; х=4; х=1/2

Answer 2

Ответ:

Объяснение:

$\displaystyle\\x^2-3x-54=0\\\\1~sposob\\\\D=b^2-4ac=3^2-4\cdot(-54)=9+216=225=15^2\\x=\frac{-b\pm\sqrt{D} }{2a} =\frac{3\pm15}{2} \\\\x_1=(3+15)/2=18/2=9\\x_2=(3-15)/2=-12/2=-6\\\\Otvet:-6;9\\\\2)~sposob\\\\x^2-9x+6x-54=0\\x(x-9)+6(x-9)=0\\(x-9)(x+6)=0\\1)x-9=0;x=9\\2)x+6=0;x=-6\\Otvet:-6;9$

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$\displaystyle\\2x^2-7x+3=0\\\\D=b^2-4ac=(-7)^2-4\cdot2\cdot3=49-24=25\\x=\frac{-b\pm\sqrt{D} }{2a} =\frac{7\pm5}{4} \\\\x_1=(7+5)/4=3\\x_2=(7-5)/4=0,5\\\\Otvet:0,5;3\\-----------------\\\\\displaystyle\\2x^2-9x+4=0\\\\\D=b^2-4ac=(-9)^2-4\cdot2\cdot4=81-32=49\\x=\frac{-b\pm\sqrt{D} }{2a} =\frac{9\pm7}{4} \\\\x_1=(9+7)/4=4\\x_2=(9-7)/4=0,5\\\\Otvet:0,5;4$