Question

решите уравнение (x-3)(x+7)=(x-4)(2x+3)+3​

Answer 1

$\displaystyle (x-3)(x+7)=(x-4)(2x+3)+3\\x^2+7x-3x-21=2x^2+3x-8x-12+3\\x^2+4x-21=2x^2-5x-9\\x^2+4x-21-2x^2+5x+9=0\\-x^2+9x-12=0\\x^2-9x+12=0\\a=1,b=-9,c=12\\\\x=\frac{-(-9)б\sqrt{(-9)^2-4*1*12} }{2*1}=\frac{9б\sqrt{81-48} }{2}=\frac{9б\sqrt{33} }{2}$