Question

Решите плиз! Очень надо!

Answer 1

$485.;a);(x+4)(x+5)=20\x^2+9x+20=20\x^2+9x=0\x(x+9)=0\x_1=0,;x_2=-9\\b);(x+5)(x-5)=24\x-25=24\x=49\\c);5(7-2x)=2x(x-5)\35-10x=2x^2-10x\2x^2=35\x^2=17,5\x=pmsqrt{17,5}\\d);x(3x-4)=2(5-2x)\3x^2-4x=10-4x\3x^2=10\x^2=frac{10}3\x=pmsqrt{frac{10}3}$

$496.;a);0,02x^2+0,005x=0\0,005x(4x+1)=0\x_1=0,;x_2=-frac14\\b);frac{x^2}3=frac x6\6x^2=3x\6x^2-3x=0\3x(2x-1)=0\x_1=0,;frac12\\c);frac1{100}=frac{x^2}{10}\100x^2=10\x^2=10\x=pmsqrt{10}$

$497.;a);x^3-x=0\x(x^2-1)=0\x_1=0,;x_2=-1,;x_3=1\\b);x^3+4x^2=0\x^2(x+4)=0\x=0,;x=-4\\c);9x^3-x=0\x(9x^2-1)=0\x_1=0,;x_2=-frac13,;x_3=frac13$