Question

Решите пожалуйста!!! 3x^2-11x+15=0 15x^2+11x+2=0    7x^2-3x=0    

Answer 1

$3x^{2}-11x+15=0\\D=b^{2}-4ac=11^{2}-4*3*5=-59\\Net korney\\\\15x^{2}+11x+2=0\\D=b^{2}-4ac=11^{2}-4*15*2=1\\x_{1,2}= \frac{-b+-\sqrt{D} }{2a} = \frac{-11+-1}{30} \\x_{1}=-\frac{1}{3}\\x_{2}=-0,4\\\\7x^{2}-3x=0\\x(7x-3)=0\\x_{1}=0 \\7x-3=0\\7x=3\\x_{2}=\frac{3}{7}$